Commit Graph

86 Commits

Author SHA1 Message Date
Daniel Vetter
1ec9e26dda drm/i915: Consolidate binding parameters into flags
Anything more than just one bool parameter is just a pain to read,
symbolic constants are much better.

Split out from Chris' vma-binding rework patch.

v2: Undo the behaviour change in object_pin that Chris spotted.

v3: Split out misplaced hunk to handle set_cache_level errors,
spotted by Jani.

v4: Keep the current over-zealous binding logic in the execbuffer code
working with a quick hack while the overall binding code gets shuffled
around.

v5: Reorder the PIN_ flags for more natural patch splitup.

v6: Pull out the PIN_GLOBAL split-up again.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ben Widawsky <benjamin.widawsky@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-02-14 14:16:58 +01:00
Mika Kuoppala
7f76b23aae drm/i915: check for oom when allocating private_default_ctx
Found with smatch

Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-02-04 12:10:26 +01:00
Mika Kuoppala
3fac8978f5 drm/i915: Tune down debug output when context is banned
If we have stopped rings then we know that test is running
so no need for spam. In addition, only spam when default
context gets banned.

v2: - make sure default context ban gets shown (Chris)
    - use helper for checking for default context, everywhere (Chris)

v3: - dont be quiet when debug is set (Ben, Daniel)

Reference: https://bugs.freedesktop.org/show_bug.cgi?id=73652
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-01-30 17:25:38 +01:00
Ben Widawsky
c5dc5cecf8 drm/i915: Create a USES_PPGTT macro
There are cases where we want to know if there is a full, or aliased
PPGTT. Currently, in fact the only distinction we ever need to make is
when we're using full PPGTT.

This patch is simply to promote readability and clarify for the
confusing existing usage where "aliasing" meant aliasing and full.

v2: Remove USES_ALIASING_PPGTT since there are currently no cases where
we need to check if we're using aliasing, but not full PPGTT. (Daniel)

Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-01-28 09:13:50 +01:00
Ville Syrjälä
2b7e8082b2 drm/i915: We implement WaMiSetContext_Hang
WaMiSetContext_Hang tells us that a MI_NOOP must follow MI_SET_CONTEXT.

The other thing WaMiSetContext_Hang seems to say is that URB_FENCE isn't
allowed to straddle two cachelines. But we don't issue those from the
kernel so we don't care.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-01-27 17:16:45 +01:00
Chris Wilson
42c3b603da drm/i915: Always pin the default context
Through a twisty and circuituous path it is possible to currently trick
the code into creating a default context and forgetting to pin it
immediately into the GGTT. (This requires a system using contexts without
an aliasing ppgtt, which is currently restricted to Baytrails machines
manually specifying a module parameter to force enable contexts, or
on Sandybridge and later that manually disable the aliasing ppgtt.) The
consequence is that during module unload we attempt to unpin the default
context twice and encounter a BUG remonstrating that we attempt to unpin
an unbound object.

[  161.002869] Kernel BUG at f84861f8 [verbose debug info unavailable]
[  161.002875] invalid opcode: 0000 [#1] SMP
[  161.002882] Modules linked in: coretemp kvm_intel kvm crc32_pclmul aesni_intel aes_i586 xts lrw gf128mul ablk_helper cryptd hid_sensor_accel_3d hid_sensor_gyro_3d hid_sensor_magn_3d hid_sensor_trigger industrialio_triggered_buffer kfifo_buf industrialio hid_sensor_iio_common snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_intel snd_hda_codec snd_hwdep snd_pcm snd_page_alloc snd_seq_midi snd_seq_midi_event dm_multipath scsi_dh asix ppdev usbnet snd_rawmidi mii hid_sensor_hub microcode snd_seq rfcomm bnep snd_seq_device bluetooth snd_timer snd parport_pc binfmt_misc soundcore dw_dmac_pci dw_dmac_core mac_hid lp parport dm_mirror dm_region_hash dm_log hid_generic usbhid hid i915(O-) drm_kms_helper(O) igb dca ptp pps_core i2c_algo_bit drm(O) ahci libahci video
[  161.002991] CPU: 0 PID: 2114 Comm: rmmod Tainted: G        W  O 3.13.0-rc8+ #2
[  161.002997] Hardware name: NEXCOM VTC1010/Aptio CRB, BIOS 5.6.5 09/24/2013
[  161.003004] task: dbdd6800 ti: dbe0e000 task.ti: dbe0e000
[  161.003010] EIP: 0060:[<f84861f8>] EFLAGS: 00010246 CPU: 0
[  161.003044] EIP is at i915_gem_object_ggtt_unpin+0x88/0x90 [i915]
[  161.003050] EAX: dfce3840 EBX: 00000000 ECX: dfafd690 EDX: dfce3874
[  161.003056] ESI: c0086b40 EDI: df962e00 EBP: dbe0fe1c ESP: dbe0fe0c
[  161.003062]  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
[  161.003068] CR0: 8005003b CR2: b7718000 CR3: 1bec0000 CR4: 001007f0
[  161.003076] Stack:
[  161.003081]  00afc014 00000004 c0086b40 dfafc000 dbe0fe38 f8487e5a dfaa5400 c0086b40
[  161.003099]  dfafc000 dfaa5400 dfaa5414 dbe0fe58 f84741aa 00000000 f89c34b9 dfaa5414
[  161.003117]  dfaa5400 dfaa5400 f644b000 dbe0fe6c f89a5443 dfaa5400 f8505000 f644b000
[  161.003134] Call Trace:
[  161.003169]  [<f8487e5a>] i915_gem_context_fini+0xba/0x1c0 [i915]
[  161.003202]  [<f84741aa>] i915_driver_unload+0x1fa/0x2f0 [i915]
[  161.003232]  [<f89a5443>] drm_dev_unregister+0x23/0x90 [drm]
[  161.003259]  [<f89a54ed>] drm_put_dev+0x3d/0x70 [drm]
[  161.003294]  [<f8470615>] i915_pci_remove+0x15/0x20 [i915]
[  161.003306]  [<c1338a6f>] pci_device_remove+0x2f/0xa0
[  161.003317]  [<c140c871>] __device_release_driver+0x61/0xc0
[  161.003328]  [<c140d12f>] driver_detach+0x8f/0xa0
[  161.003341]  [<c140c54f>] bus_remove_driver+0x4f/0xc0
[  161.003353]  [<c140d708>] driver_unregister+0x28/0x60
[  161.003362]  [<c10cee42>] ? stop_cpus+0x32/0x40
[  161.003372]  [<c10bd510>] ? module_refcount+0x90/0x90
[  161.003383]  [<c13378c5>] pci_unregister_driver+0x15/0x60
[  161.003413]  [<f89a739f>] drm_pci_exit+0x9f/0xb0 [drm]
[  161.003458]  [<f84e624a>] i915_exit+0x1b/0x1d [i915]
[  161.003468]  [<c10bf8a8>] SyS_delete_module+0x158/0x1f0
[  161.003480]  [<c1173d5d>] ? ____fput+0xd/0x10
[  161.003488]  [<c106f0fe>] ? task_work_run+0x7e/0xb0
[  161.003499]  [<c165a68d>] sysenter_do_call+0x12/0x28
[  161.003505] Code: 0f b6 4d f3 8d 51 0f 83 e1 f0 83 e2 0f 09 d1 84 d2 88 48 54 75 07 80 a7 91 00 00 00 7f 83 c4 04 5b 5e 5f 5d c3 8d b6 00 00 00 00 <0f> 0b 8d b6 00 00 00 00 55 89 e5 57 56 53 83 ec 64 3e 8d 74 26
[  161.003586] EIP: [<f84861f8>] i915_gem_object_ggtt_unpin+0x88/0x90 [i915] SS:ESP 0068:dbe0fe0c

v2: Rename the local variable (is_default_ctx) to avoid confusion with
the function is_default_ctx(). And correct Jesse's email address.

Reported-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=73985
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Ben Widawsky <benjamin.widawsky@intel.com>
Tested-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Ben Widawsky <benjamin.widawsky@intel.com>
[danvet: Fix up the rebase fail from my first attempt, thankfully
pointed out by Ville.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-01-27 17:16:10 +01:00
Ben Widawsky
ad1d219974 drm/i915: set ctx->initialized only after RCS
The initialized flag is used to specify a context has been initialized
and it's context is safe to load, ie. the 3d state is setup properly.
With full PPGTT, we emit the address space loads during context switch
and this currently marks a context as initialized. With full PPGTT
patches, if a client first emits a batch to !RCS, then later, RCS, the
code will mistake the context as initialized and try to reload an
uninitialized context.

1. context 1 blit // context marked as initialized, but isn't
2. context 1 render // loads random state from step 2

It is really easy to hit this with a planned upcoming patch which makes
default context reuse possible.

NOTE: This should only effect full PPGTT branches, ie. current
drm-intel-nightly.

Thanks to Chris for helping me track this down.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
[danvet: Simplify the failure scenario in the commit message according
to Chris' review a bit.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-01-10 08:21:51 +01:00
Ben Widawsky
c2cf2416ca drm/i915/bdw: Return -ENONENT on default ctx destroy
This was an accidental "ABI" change introduced during PPGTT:

commit 0eea67eb26
Author: Ben Widawsky <ben@bwidawsk.net>
Date:   Fri Dec 6 14:11:19 2013 -0800

    drm/i915: Create a per file_priv default context

The failure test application actually tests the return type. The other
option is to simply change the test.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-01-10 08:21:50 +01:00
Ben Widawsky
72ad5c45f0 drm/i915/ppgtt: Fix ioctl errno for "no such context"
Without this fix the ioctls silently succeeded (but actually did
nothing).

It makes all the code which calls into this function way too confusing.

v2: Fix destroy IOCTL as well

v3: Clarify the other two callers of i915_gem_context_get() to never
check for NULL. (Mika)

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=72903
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Testcase: igt/gem_ctx_exec/basic
[danvet: Fix up the commit message and actually bother to mention the
testcase this fixes.]
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-01-07 08:50:11 +01:00
Ben Widawsky
7e0d96bc03 drm/i915: Use multiple VMs -- the point of no return
As with processes which run on the CPU, the goal of multiple VMs is to
provide process isolation. Specific to GEN, there is also the ability to
map more objects per process (2GB each instead of 2Gb-2k total).

For the most part, all the pipes have been laid, and all we need to do
is remove asserts and actually start changing address spaces with the
context switch. Since prior to this we've converted the setting of the
page tables to a streamed version, this is quite easy.

One important thing to point out (since it'd been hotly contested) is
that with this patch, every context created will have it's own address
space (provided the HW can do it).

v2: Disable BDW on rebase

NOTE: I tried to make this commit as small as possible. I needed one
place where I could "turn everything on" and that is here. It could be
split into finer commits, but I didn't really see much point.

Cc: Eric Anholt <eric@anholt.net>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-12-18 16:24:52 +01:00
Daniel Vetter
3d7f0f9dcc Merge commit drm-intel-fixes into topic/ppgtt
I need the tricky do_switch fix before I can merge the final piece of
the ppgtt enabling puzzle. Otherwise the conflict will be a real pain
to resolve since the do_switch hunk from -fixes must be placed at the
exact right place within a hunk in the next patch.

Conflicts:
	drivers/gpu/drm/i915/i915_gem_context.c
	drivers/gpu/drm/i915/i915_gem_execbuffer.c
	drivers/gpu/drm/i915/intel_display.c

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-12-18 16:23:37 +01:00
Ben Widawsky
41bde5535a drm/i915: Get context early in execbuf
We need to have the address space when reserving space for the objects.
Since the address space and context are tied together, and reserve
occurs before context switch (for good reason), we must lookup our
context earlier in the process.

This leaves some room for optimizations where we no longer need to use
ctx_id in certain places. This will be addressed in a subsequent patch.

Important tricky bit:
Because slow relocations during execbuffer drop struct_mutex

Perhaps it would be best to acquire the reference when we get the
context, but I'll save that for another day (note I have written the
patch before, and I found the changes required to be uglier than this).

Note that since we currently access everything via context id, and not
the data structure this is fine, though not desirable. The next change
attempts to get the context only once via the context ID idr lookup, and
as such, the following can happen:

CTX-A is created, refcount = 1
CTX-A execbuf, mutex dropped
close IOCTL called on CTX-A, refcount = 0
CTX-A resumes in execbuf.

v2: Rebased on top of
commit b6359918b8
Author: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Date:   Wed Oct 30 15:44:16 2013 +0200

    drm/i915: add i915_get_reset_stats_ioctl

v3: Rebased on top of
commit 25b3dfc87b
Author: Mika Westerberg <mika.westerberg@linux.intel.com>
Date:   Tue Nov 12 11:57:30 2013 +0200

Author: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Date:   Tue Nov 26 16:14:33 2013 +0200

    drm/i915: check context reset stats before relocations

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-12-18 15:52:42 +01:00
Ben Widawsky
c482972a08 drm/i915: Piggy back hangstats off of contexts
To simplify the codepaths somewhat, we can simply always create a
context. Contexts already keep hangstat information. This prevents us
from having to differentiate at other parts in the code.

There is allocation overhead, but it should not be measurable.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-12-18 15:51:58 +01:00
Ben Widawsky
0eea67eb26 drm/i915: Create a per file_priv default context
Every file will get it's own context, and we use this context instead of
the default context. The default context still exists for future
shrinker usage as well as reset handling.

v2: Updated to address Mika's recent context guilty changes
Some more changes around this come up in later patches as well.

v3: Use a fake context to avoid allocation for the !HAS_HW_CONTEXT case.
I've tried the alternatives. This looks the best to me.
Removed hangstat stuff from v2 - for a separate patch
Demote failed PPGTT set to DRM_DEBUG_DRIVER since it can now be invoked
easily from userspace.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-12-18 15:44:29 +01:00
Ben Widawsky
bdf4fd7ea0 drm/i915: Do aliasing PPGTT init with contexts
We have a default context which suits the aliasing PPGTT well. Tie them
together so it looks like any other context/PPGTT pair. This makes the
code cleaner as it won't have to special case aliasing as often.

The patch has one slightly tricky part in the default context creation
function. In the future (and on aliased setup) we create a new VM for a
context (potentially). However, if we have aliasing PPGTT, which occurs
at this point in time for all platforms GEN6+, we can simply manage the
refcounting to allow things to behave as normal. Now is a good time to
recall that the aliasing_ppgtt doesn't have a real VM, it uses the GGTT
drm_mm.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-12-18 15:32:14 +01:00
Ben Widawsky
c7c48dfdff drm/i915: Add VM to context
Pretty straightforward so far except for the bit about the refcounting.
The PPGTT will potentially be shared amongst multiple contexts. Because
contexts themselves have a refcounted lifecycle, the easiest way to
manage this will be to refcount the PPGTT. To acheive this, we piggy
back off of the existing context refcount, and will increment and
decrement the PPGTT refcount with context creation, and destruction.

To put it more clearly, if context A, and context B both use PPGTT 0, we
can't free the PPGTT until both A, and B are destroyed.

Note that because the PPGTT is permanently pinned (for now), it really
just matters for the PPGTT destruction, as opposed to making space under
memory pressure.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-12-18 15:31:20 +01:00
Ben Widawsky
a45d0f6a7f drm/i915: Generalize default context setup
The plan to to make every file descriptor have a default context. To
accommodate this, generalize out default context setup function so it
can be used at file open time.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-12-18 15:27:56 +01:00
Ben Widawsky
2fa48d8d4a drm/i915: Split context enabling from init
We **need** to do this for exactly 1 reason, because we want to embed a
PPGTT into the context, but we don't want to special case the default
context.

To achieve that, we must be able to initialize contexts after the GTT is
setup (so we can allocate and pin the default context's BO), but before
the PPGTT and rings are initialized. This is because, currently, context
initialization requires ring usage. We don't have rings until after the
GTT is setup. If we split the enabling part of context initialization,
the part requiring the ringbuffer, we can untangle this, and then later
embed the PPGTT

Incidentally this allows us to also adhere to the original design of
context init/fini in future patches: they were only ever meant to be
called at driver load and unload.

v2: Move hw_contexts_disabled test in i915_gem_context_enable() (Chris)

v3: BUG_ON after checking for disabled contexts. Or else it blows up pre
gen6 (Ben)

v4: Forward port
Modified enable for each ring, since that patch is earlier in the series
Dropped ring arg from create_default_context so it can be used by others

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-12-18 15:27:55 +01:00
Ben Widawsky
acce9ffa48 drm/i915: Better reset handling for contexts
This patch adds to changes for contexts on reset:
Sets last context to default - this will prevent the context switch
happening after a reset. That switch is not possible because the
rings are hung during reset and context switch requires reset. This
behavior will need to be reworked in the future, but this is what we
want for now.

In the future, we'll also want to reset the guilty context to
uninitialized. We should wait for ARB_Robustness related code to land
for that.

This is somewhat for paranoia.  Because we really don't know what the
GPU was doing when it hung, or the state it was in (mid context write,
for example), later restoring the context is a bad idea. By setting the
flag to not initialized, the next load of that context will not restore
the state, and thus on the subsequent switch away from the context will
overwrite the old data.

NOTE: This code needs a fixup when we actually have multiple VMs. The
issue that can occur is inactive objects in a VM will need to be
destroyed before the last context unref. This can now happen via the
fake switch introduced in this patch (and it other ways in the future)

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-12-18 15:27:54 +01:00
Ben Widawsky
0009e46cd5 drm/i915: Track which ring a context ran on
Previously we dropped the association of a context to a ring. It is
however very important to know which ring a context ran on (we could
have reused the other member, but I was nitpicky).

This is very important when we switch address spaces, which unlike
context objects, do change per ring.

As an example, if we have:

        RCS   BCS
ctx            A
ctx      A
ctx      B
ctx            B

Without tracking the last ring B ran on, we wouldn't know to switch the
address space on BCS in the last row.

As a result, we no longer need to track which ring a context "belongs"
to, as it never really made much sense anyway.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-12-18 15:27:54 +01:00
Ben Widawsky
67e3d2979b drm/i915: Permit contexts on all rings
If we want to use contexts in more abstract terms (specifically with
PPGTT in mind), we need to allow them to be specified for any ring.

Since the upcoming patches will bring about the use of multiple address
spaces, and each ring needs to have an address space programmed (which
we intend to do at context switch time), we can no longer only use RCS.

With multiple rings having a last context, we must now unreference these
contexts.

NOTE: This commit requires an update to intel-gpu-tools to make it not
fail.

v2: Rebased with some logical conflicts.
Squashed in the context fini refcount patch

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-12-18 15:27:53 +01:00
Ben Widawsky
b731d33d05 drm/i915: relax context alignment
With the introduction of contexts per fd in the future, one can easily
envision more contexts being used. We do not have an easy remedy to
reduce the space requirements of the contexts, we can make things
slightly better by using less stringent alignments on later hardware.

Ville: Since I can almost predict you'll point this out. I can no longer
find the docs which specify the 64k requirement on certain gen6 SKUs. If
you'd like to change that too, be my guest.

CC: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-12-18 15:27:52 +01:00
Ben Widawsky
e422b888eb drm/i915: Add a context open function
We'll be doing a bit more stuff with each file, so having our own open
function should make things clean.

This also allows us to easily add conditionals for stuff we don't want
to do when we don't have HW contexts.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-12-18 15:27:51 +01:00
Ben Widawsky
6f65e29aca drm/i915: Create bind/unbind abstraction for VMAs
To sum up what goes on here, we abstract the vma binding, similarly to
the previous object binding. This helps for distinguishing legacy
binding, versus modern binding. To keep the code churn as minimal as
possible, I am leaving in insert_entries(). It serves as the per
platform pte writing basically. bind_vma and insert_entries do share a
lot of similarities, and I did have designs to combine the two, but as
mentioned already... too much churn in an already massive patchset.

What follows are the 3 commits which existed discretely in the original
submissions. Upon rebasing on Broadwell support, it became clear that
separation was not good, and only made for more error prone code. Below
are the 3 commit messages with all their history.

drm/i915: Add bind/unbind object functions to VMA
drm/i915: Use the new vm [un]bind functions
drm/i915: reduce vm->insert_entries() usage

drm/i915: Add bind/unbind object functions to VMA

As we plumb the code with more VM information, it has become more
obvious that the easiest way to deal with bind and unbind is to simply
put the function pointers in the vm, and let those choose the correct
way to handle the page table updates. This change allows many places in
the code to simply be vm->bind, and not have to worry about
distinguishing PPGTT vs GGTT.

Notice that this patch has no impact on functionality. I've decided to
save the actual change until the next patch because I think it's easier
to review that way. I'm happy to squash the two, or let Daniel do it on
merge.

v2:
Make ggtt handle the quirky aliasing ppgtt
Add flags to bind object to support above
Don't ever call bind/unbind directly for PPGTT until we have real, full
PPGTT (use NULLs to assert this)
Make sure we rebind the ggtt if there already is a ggtt binding.  This
happens on set cache levels.
Use VMA for bind/unbind (Daniel, Ben)

v3: Reorganize ggtt_vma_bind to be more concise and easier to read
(Ville). Change logic in unbind to only unbind ggtt when there is a
global mapping, and to remove a redundant check if the aliasing ppgtt
exists.

v4: Make the bind function a bit smarter about the cache levels to avoid
unnecessary multiple remaps. "I accept it is a wart, I think unifying
the pin_vma / bind_vma could be unified later" (Chris)
Removed the git notes, and put version info here. (Daniel)

v5: Update the comment to not suck (Chris)

v6:
Move bind/unbind to the VMA. It makes more sense in the VMA structure
(always has, but I was previously lazy). With this change, it will allow
us to keep a distinct insert_entries.

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>

drm/i915: Use the new vm [un]bind functions

Building on the last patch which created the new function pointers in
the VM for bind/unbind, here we actually put those new function pointers
to use.

Split out as a separate patch to aid in review. I'm fine with squashing
into the previous patch if people request it.

v2: Updated to address the smart ggtt which can do aliasing as needed
Make sure we bind to global gtt when mappable and fenceable. I thought
we could get away without this initialy, but we cannot.

v3: Make the global GTT binding explicitly use the ggtt VM for
bind_vma(). While at it, use the new ggtt_vma helper (Chris)

At this point the original mailing list thread diverges. ie.

v4^:
use target_obj instead of obj for gen6 relocate_entry
vma->bind_vma() can be called safely during pin. So simply do that
instead of the complicated conditionals.
Don't restore PPGTT bound objects on resume path
Bug fix in resume path for globally bound Bos
Properly handle secure dispatch
Rebased on vma bind/unbind conversion

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>

drm/i915: reduce vm->insert_entries() usage

FKA: drm/i915: eliminate vm->insert_entries()

With bind/unbind function pointers in place, we no longer need
insert_entries. We could, and want, to remove clear_range, however it's
not totally easy at this point. Since it's used in a couple of place
still that don't only deal in objects: setup, ppgtt init, and restore
gtt mappings.

v2: Don't actually remove insert_entries, just limit its usage. It will
be useful when we introduce gen8. It will always be called from the vma
bind/unbind.

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> (v1)
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-12-18 15:27:50 +01:00
Ben Widawsky
d7f46fc4e7 drm/i915: Make pin count per VMA
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-12-18 15:27:49 +01:00
Daniel Vetter
acc240d41e drm/i915: Fix use-after-free in do_switch
So apparently under ridiculous amounts of memory pressure we can get
into trouble in do_switch when we try to move the old hw context
backing storage object onto the active lists.

With list debugging enabled that usually results in us chasing a
poisoned pointer - which means we've hit upon a vma that has been
removed from all lrus with list_del (and then deallocated, so it's a
real use-after free).

Ian Lister has done some great callchain chasing and noticed that we
can reenter do_switch:

i915_gem_do_execbuffer()

i915_switch_context()

do_switch()
   from = ring->last_context;
   i915_gem_object_pin()

      i915_gem_object_bind_to_gtt()
         ret = drm_mm_insert_node_in_range_generic();
         // If the above call fails then it will try i915_gem_evict_something()
         // If that fails it will call i915_gem_evict_everything() ...
	 i915_gem_evict_everything()
	    i915_gpu_idle()
	       i915_switch_context(DEFAULT_CONTEXT)

Like with everything else where the shrinker or eviction code can
invalidate pointers we need to reload relevant state.

Note that there's no need to recheck whether a context switch is still
required because:

- Doing a switch to the same context is harmless (besides wasting a
  bit of energy).

- This can only happen with the default context. But since that one's
  pinned we'll never call down into evict_everything under normal
  circumstances. Note that there's a little driver bringup fun
  involved namely that we could recourse into do_switch for the
  initial switch. Atm we're fine since we assign the context pointer
  only after the call to do_switch at driver load or resume time. And
  in the gpu reset case we skip the entire setup sequence (which might
  be a bug on its own, but definitely not this one here).

Cc'ing stable since apparently ChromeOS guys are seeing this in the
wild (and not just on artificial stress tests), see the reference.

Note that in upstream code doesn't calle evict_everything directly
from evict_something, that's an extension in this product branch. But
we can still hit upon this bug (and apparently we do, see the linked
backtraces). I've noticed this while trying to construct a testcase
for this bug and utterly failed to provoke it. It looks like we need
to driver the system squarly into the lowmem wall and provoke the
shrinker to evict the context object by doing the last-ditch
evict_everything call.

Aside: There's currently no means to get a badly-fragmenting hw
context object away from a bad spot in the upstream code. We should
fix this by at least adding some code to evict_something to handle hw
contexts.

References: https://code.google.com/p/chromium/issues/detail?id=248191
Reported-by: Ian Lister <ian.lister@intel.com>
Cc: Ian Lister <ian.lister@intel.com>
Cc: stable@vger.kernel.org
Cc: Ben Widawsky <benjamin.widawsky@intel.com>
Cc: Stéphane Marchesin <marcheu@chromium.org>
Cc: Bloomfield, Jon <jon.bloomfield@intel.com>
Tested-by: Rafael Barbalho <rafael.barbalho@intel.com>
Reviewed-by: Ian Lister <ian.lister@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-12-06 13:09:11 +01:00
Chris Wilson
0d1430a3f4 drm/i915: Hold mutex across i915_gem_release
Inorder to serialise the closing of the file descriptor and its
subsequent release of client requests with i915_gem_free_request(), we
need to hold the struct_mutex in i915_gem_release(). Failing to do so
has the potential to trigger an OOPS, later with a use-after-free.

Testcase: igt/gem_close_race
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=70874
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=71029
Reported-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-12-04 16:57:02 +01:00
Ben Widawsky
2f88542607 drm/i915: Remove defunct ctx switch comments
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-11-26 10:12:16 +01:00
Daniel Vetter
c09cd6e969 Merge branch 'backlight-rework' into drm-intel-next-queued
Pull in Jani's backlight rework branch. This was merged through a
separate branch to be able to sort out the Broadwell conflicts
properly before pulling it into the main development branch.

Conflicts:
	drivers/gpu/drm/i915/intel_display.c

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-11-15 10:02:39 +01:00
Ben Widawsky
8897644a6d drm/i915/bdw: HW context support
BDW context sizes varies a bit.

v2: Squash in fixup for the hw context size from Ben.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net> (v1)
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-11-08 18:09:37 +01:00
Ben Widawsky
8245be3139 drm/i915: Require HW contexts (when possible)
v2: Fixed the botched locking on init_hw failure in i915_reset (Ville)
Call cleanup_ringbuffer on failed context create in init_hw (Ville)

v3: Add dev argument ti clean_ringbuffer

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-11-07 09:35:44 +01:00
Ben Widawsky
71b76d004f drm/i915: cleanup context fini
I had this lying around from he original PPGTT series, and thought we
might try to get it in by itself.

With the introduction of context refcounting we never explicitly
ref/unref the backing object. As such, the previous fix was a bit wonky.

Aside from fixing the above, this patch also puts us in good shape for
an upcoming patch which allows a failure to occur in between
context_init and the first do_switch.

CC: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-10-16 11:08:30 +02:00
Ben Widawsky
e2d05a8b1e drm/i915: Convert active API to VMA
Even though we track object activity and not VMA, because we have the
active_list be based on the VM, it makes the most sense to use VMAs in
the APIs.

NOTE: Daniel intends to eventually rip out active/inactive LRUs, but for
now, leave them be.

v2: Remove leftover hunk from the previous patch which didn't keep
i915_gem_object_move_to_active. That patch had to rely on the ring to
get the dev instead of the obj. (Chris)

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-10-01 07:45:21 +02:00
Ben Widawsky
3ccfd19dea drm/i915: Do remaps for all contexts
On both Ivybridge and Haswell, row remapping information is saved and
restored with context. This means, we never actually properly supported
the l3 remapping because our sysfs interface is asynchronous (and not
tied to any context), and the known faulty HW would be reused by the
next context to run.

Not that due to the asynchronous nature of the sysfs entry, there is no
point modifying the registers for the existing context. Instead we set a
flag for all contexts to load the correct remapping information on the
next run. Interested clients can use debugfs to determine whether or not
the row has been remapped.

One could propose at this point that we just do the remapping in the
kernel. I guess since we have to maintain the sysfs interface anyway,
I'm not sure how useful it is, and I do like keeping the policy in
userspace; (it wasn't my original decision to make the
interface the way it is, so I'm not attached).

v2: Force a context switch when we have a remap on the next switch.
(Ville)
Don't let userspace use the interface with disabled contexts.

v3: Don't force a context switch, just let it nop
Improper context slice remap initialization, 1<<1 instead of 1<<i, but I
rewrote it to avoid a second round of confusion.
Error print moved to error path (All Ville)
Added a comment on why the slice remap initialization happens.

CC: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-09-19 20:39:56 +02:00
Ben Widawsky
a33afea5ff drm/i915: Keep a list of all contexts
I have implemented this patch before without creating a separate list
(I'm having trouble finding the links, but the messages ids are:
<1364942743-6041-2-git-send-email-ben@bwidawsk.net>
<1365118914-15753-9-git-send-email-ben@bwidawsk.net>)

However, the code is much simpler to just use a list and it makes the
code from the next patch a lot more pretty.

As you'll see in the next patch, the reason for this is to be able to
specify when a context needs to get L3 remapping. More details there.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-09-19 20:39:43 +02:00
Damien Lespiau
508842a036 drm/i915: It's its!
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Acked-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-09-04 17:34:54 +02:00
Chris Wilson
c0321e2c5a drm/i915: Do not add an interrupt for a context switch
We use the request to ensure we hold a reference to the context for the
duration that it remains in use by the ring. Each request only holds a
reference to the current context, hence we emit a request after
switching contexts with the final reference to the old context. However,
the extra interrupt caused by that request is not useful (no timing
critical function will wait for the context object), instead the overhead
of servicing the IRQ shows up in some (lightweight) benchmarks. In order
to keep the useful property of using the request to manage the context
lifetime, we want to add a dummy request that is associated with the
interrupt from the subsequent real request following the batch.

The extra interrupt was added as a side-effect of using
i915_add_request() in

commit 112522f678
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Thu May 2 16:48:07 2013 +0300

    drm/i915: put context upon switching

v2: Daniel convinced me that the request here was solely for context
lifetime tracking and that we have the active ref to keep the object
alive whilst the MI_SET_CONTEXT. So the only concern then is which
context should get the blame for MI_SET_CONTEXT failing. The old scheme
added a request for the old context so that any hang upto and including
the switch away would mark the old context as guilty. Now any hang here
implicates the new context. However since we have already gone through a
complete flush with the last context in its last request, and all that
lies in no-man's-land is an invalidate flush and the MI_SET_CONTEXT, we
should be safe in not unduly placing blame on the new context.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ben Widawsky <ben@bwidawsk.net>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-09-04 17:34:53 +02:00
Ben Widawsky
ca191b1313 drm/i915: mm_list is per VMA
formerly: "drm/i915: Create VMAs (part 5) - move mm_list"

The mm_list is used for the active/inactive LRUs. Since those LRUs are
per address space, the link should be per VMx .

Because we'll only ever have 1 VMA before this point, it's not incorrect
to defer this change until this point in the patch series, and doing it
here makes the change much easier to understand.

Shamelessly manipulated out of Daniel:
"active/inactive stuff is used by eviction when we run out of address
space, so needs to be per-vma and per-address space. Bound/unbound otoh
is used by the shrinker which only cares about the amount of memory used
and not one bit about in which address space this memory is all used in.
Of course to actual kick out an object we need to unbind it from every
address space, but for that we have the per-object list of vmas."

v2: only bump GGTT LRU in i915_gem_object_set_to_gtt_domain (Chris)

v3: Moved earlier in the series

v4: Add dropped message from v3

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
[danvet: Frob patch to apply and use vma->node.size directly as
discused with Ben. Also drop a needles BUG_ON before move_to_inactive,
the function itself has the same check.]
[danvet 2nd: Rebase on top of the lost "drm/i915: Cleanup more of VMA
in destroy", specifically unlink the vma from the mm_list in
vma_unbind (to keep it symmetric with bind_to_vm) instead of
vma_destroy.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-08-08 14:06:58 +02:00
Chris Wilson
350ec881d9 drm/i915: Rename I915_CACHE_MLC_LLC to L3_LLC for Ivybridge
MLC_LLC was never validated for Sandybridge and was superseded by a new
level of cacheing for the GPU in Ivybridge. Update our names to be
consistent with usage, and in the process stop setting the unwanted bit
on Sandybridge.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
[danvet: s/BUG/WARN_ON(1) bikeshed.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-08-06 16:35:30 +02:00
Ben Widawsky
c37e220461 drm/i915: Add VM to pin
To verbalize it, one can say, "pin an object into the given address
space." The semantics of pinning remain the same otherwise.

Certain objects will always have to be bound into the global GTT.
Therefore, global GTT is a special case, and keep a special interface
around for it (i915_gem_obj_ggtt_pin).

v2: s/i915_gem_ggtt_pin/i915_gem_obj_ggtt_pin

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-08-05 19:04:09 +02:00
Chris Wilson
11fa338404 drm/i915: Fix retrieval of hangcheck stats
The default context is always supported (as it contains the global
hangcheck stats) and the contexts for hangcheck are not limited
to any ring.

References: https://bugs.freedesktop.org/show_bug.cgi?id=65845
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-07-16 10:40:25 +02:00
Ben Widawsky
f343c5f647 drm/i915: Getter/setter for object attributes
Soon we want to gut a lot of our existing assumptions how many address
spaces an object can live in, and in doing so, embed the drm_mm_node in
the object (and later the VMA).

It's possible in the future we'll want to add more getter/setter
methods, but for now this is enough to enable the VMAs.

v2: Reworked commit message (Ben)
Added comments to the main functions (Ben)
sed -i "s/i915_gem_obj_set_color/i915_gem_obj_ggtt_set_color/" drivers/gpu/drm/i915/*.[ch]
sed -i "s/i915_gem_obj_bound/i915_gem_obj_ggtt_bound/" drivers/gpu/drm/i915/*.[ch]
sed -i "s/i915_gem_obj_size/i915_gem_obj_ggtt_size/" drivers/gpu/drm/i915/*.[ch]
sed -i "s/i915_gem_obj_offset/i915_gem_obj_ggtt_offset/" drivers/gpu/drm/i915/*.[ch]
(Daniel)

v3: Rebased on new reserve_node patch
Changed DRM_DEBUG_KMS to actually work (will need fixing later)

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-07-08 22:04:34 +02:00
Ben Widawsky
a0de80a0e0 drm/i915: Fix context sizes on HSW
With updates to the spec, we can actually see the context layout, and
how many dwords are allocated. That table suggests we need 70720 bytes
per HW context. Rounded up, this is 18 pages. Looking at what lives
after the current 4 pages we use, I can't see too much important (mostly
it's d3d related), but there are a couple of things which look scary. I
am hopeful this can explain some of our odd HSW failures.

v2: Make the context only 17 pages. The power context space isn't used
ever, and execlists aren't used in our driver, making the actual total
66944 bytes.

v3: Add a comment to the code. (Jesse & Paulo)

Reported-by: "Azad, Vinit" <vinit.azad@intel.com>
Cc: stable@vger.kernel.org
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-07-01 11:14:54 +02:00
Mika Kuoppala
0025c0772d drm/i915: change i915_add_request to macro
Only execbuffer needed all the parameters on i915_add_request().
By putting __i915_add_request behind macro, all current callsites
become cleaner. Following patch will introduce a new parameter
for __i915_add_request. With this patch, only the relevant callsite
will reflect the change making commit smaller and easier to understand.

v2: _i915_add_request as function name (Chris Wilson)

v3: change name __i915_add_request and fix ordering of params (Ben Widawsky)

Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-06-13 17:42:15 +02:00
Mika Kuoppala
c0bb617a70 drm/i915: add i915_gem_context_get_hang_stats()
To get context hang statistics for specified context,
add i915_gem_context_get_hang_stats().

For arb-robustness, every context needs to have its own
hang statistics tracking. Added function will return
the user specified context statistics or in case of
default context, statistics from drm_i915_file_private.

v2: handle default context inside get_reset_state

v3: return struct pointer instead of passing it in as param
    (Chris Wilson)

Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-06-13 17:42:15 +02:00
Ben Widawsky
bb0364130f drm/i915: context debug messages
Add some debug messages to help figure out what goes wrong on context
initialization.

Later in the PPGTT series, I ended up having a lot of failures after
reset. In many cases it was extra difficult to debug because I hadn't
even realized that contexts failed to reinitialize after reset (again an
artifact of some later patches).

This fairly benign patch does help debug some potential issues which
arise later.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-05-31 20:53:58 +02:00
Damien Lespiau
8693a82487 drm/i915: Add references to some workaround we implement
We did not mention the workaround name when implementing those. This
should help us track what we already implement.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-05-10 21:56:34 +02:00
Ben Widawsky
186507e9e8 drm/i915: Assert mutex_is_locked on context lookup
Because our context refcounting doesn't grab a ref at lookup time, it is
unsafe to do so without the lock.

NOTE: We don't have an easy way to put the assertion in the lookup
function which is where this really belongs. Context switching is good
enough because it actually asserts even more correctness by protecting
the default_context.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
[danvet: s/BUG/WARN/]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-05-06 11:30:29 +02:00
Chris Wilson
112522f678 drm/i915: put context upon switching
In order to be notified of when the context and all of its associated
objects is idle (for if the context maps to a ppgtt) we need a callback
from the retire handler. We can arrange this by using the kref_get/put
of the context for request tracking and by inserting a request to
demarque the switch away from the old context.

[Ben: fixed minor error to patch compile, AND s/last_context/from/]
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-05-06 11:20:48 +02:00
Mika Kuoppala
168f836602 drm/i915: unreference default context on module unload
Before module unload is called, gpu_idle() will switch
to default context. This will increment ref count of base
object as the default context is 'running' on module unload
time. Unreference the drm object so that when context
is freed, base object is freed as well.

v2: added comment to explain the refcounts (Ben Widawsky)

Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-05-03 18:19:56 +02:00