Commit Graph

68539 Commits

Author SHA1 Message Date
Chris Wilson
2d7ef395b3 drm/i915: Immediately discard any backing storage for uneeded objects
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
2009-09-23 01:10:37 +01:00
Chris Wilson
963b483691 drm/i915: Do not mis-classify clean objects as purgeable
Whilst cleaning up the patches for submission, I mis-classified non-dirty
objects as purgeable. This was causing the backing pages for those
objects to be evicted under memory-pressure, discarding valid and
unreplaceable texture data.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
2009-09-23 01:10:36 +01:00
Chris Wilson
13a05fd978 drm/i915: Whitespace correction for madv
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
2009-09-23 01:10:35 +01:00
Chris Wilson
a32808c0a1 drm/i915: BUG_ON page refleak during unbind
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
2009-09-23 01:10:21 +01:00
Chris Wilson
9a1e2582d8 drm/i915: Search harder for a reusable object
As evict_something() is called by routines that do not repeatedly search
again, try harder in the initial search to find an object that matches
the request.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
2009-09-23 01:05:28 +01:00
Chris Wilson
ab5ee57650 drm/i915: Clean up evict from list.
First the routine attempted to unlock a mutex it did not own along the
error path.

Secondly the routine should never be called on any list but the inactive
one, since we attempt to unbind those objects, so fix the calling semantics.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
2009-09-23 01:05:26 +01:00
Chris Wilson
1c5d22f76d drm/i915: Add tracepoints
By adding tracepoint equivalents for WATCH_BUF/EXEC we are able to monitor
the lifetimes of objects, requests and significant events. These events can
then be probed using the tracing frameworks, such as systemtap and, in
particular, perf.

For example to record the stack trace for every GPU stall during a run, use

  $ perf record -e i915:i915_gem_request_wait_begin -c 1 -g

And

  $ perf report

to view the results.

[Updated to fix compilation issues caused.]
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Ben Gamari <bgamari@gmail.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
2009-09-23 01:05:21 +01:00
Jesse Barnes
74dff28223 drm/i915: framebuffer compression for GM45+
Add support for framebuffer compression on GM45 and above.  Removes
some unnecessary I915_HAS_FBC checks as well (this is now part of the
FBC display function).

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
2009-09-21 15:47:38 -07:00
Jesse Barnes
e70236a8d3 drm/i915: split display functions by chip type
This patch splits out several of the display functions into a separate
display function table to avoid tons of chipset specific if..else
if..else if blocks all over.  There are more opportunities for this
(some noted in the structure defintition); so more cleanup patches will
follow.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
2009-09-21 15:47:33 -07:00
Chris Wilson
8542a0bbbb drm/i915: Skip the sanity checks if the current relocation is valid
If the presumed_offset as feed to userspace and returned to the kernel
from a previous execbuffer is still valid, then we do not need to rewrite
the relocation entry and may skip the offset sanity checks.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-18 15:31:39 -07:00
Chris Wilson
cd0b9fb400 drm/i915: Check that the relocation points to within the target
Eric noted a potential concern with the low bits not being strictly used
as part of the absolute offset (instead part of the command stream to the
GPU), but in practice that should not be an issue.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Tested-by: Andy Whitcroft <apw@canonical.com>
Cc: Eric Anholt <eric@anholt.net>
CC: stable@kernel.org
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-18 15:31:21 -07:00
Jesse Barnes
edb8195642 drm/i915: correct FBC update when pipe base update occurs
We usually don't have an SAREA, and we always want to update the FBC
status anyway, so move the update up above the various master/sarea
checks.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 17:06:47 -07:00
Jesse Barnes
7121413f2a drm/i915: blacklist Acer AspireOne lid status
It reports closed when open, leading to "no outputs found" at startup
unless a VGA cable is plugged in.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 15:45:26 -07:00
Jesse Barnes
d660467c3f drm/i915: prevent FIFO calculation overflows on 32 bits with high dotclocks
A very high dotclock (e.g. 229500kHz as reported by Anton) can cause
the entries_required variable to overflow, potentially leading to a
FIFO watermark value that's too low to support the given mode.  Split
the division across the calculation to avoid this.

Cc: stable@kernel.org
Reported-by: Anton Khirnov <wyskas@gmail.com>
Tested-by: Anton Khirnov <wyskas@gmail.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:46:48 -07:00
Jaswinder Singh Rajput
decbbcda29 drm/i915: intel_display.c handle latency variable efficiently
By handling latency variable efficiently we also get rid of this warning :

  CC [M]  drivers/gpu/drm/i915/intel_display.o
drivers/gpu/drm/i915/intel_display.c: In function ‘igd_enable_cxsr’:
drivers/gpu/drm/i915/intel_display.c:1918: warning: ‘latency’ may be used uninitialized in this function

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:43:34 -07:00
Zhenyu Wang
b7e53aba2f drm/i915: remove restore in resume
Don't need extra config restore like for intel_agp, which
might cause resume hang issue found by Alan on 845G.

Cc: Stable Team <stable@kernel.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:43:33 -07:00
Chris Wilson
07f73f6912 drm/i915: Improve behaviour under memory pressure
Due to the necessity of having to take the struct_mutex, the i915
shrinker can not free the inactive lists if we fail to allocate memory
whilst processing a batch buffer, triggering an OOM and an ENOMEM that
is reported back to userspace. In order to fare better under such
circumstances we need to manually retry a failed allocation after
evicting inactive buffers.

To do so involves 3 steps:
1. Marking the backing shm pages as NORETRY.
2. Updating the get_pages() callers to evict something on failure and then
   retry.
3. Revamping the evict something logic to be smarter about the required
   buffer size and prefer to use volatile or clean inactive pages.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:43:32 -07:00
Chris Wilson
3ef94daae7 drm/i915: Add ioctl to set 'purgeability' of objects
Similar to the madvise() concept, the application may wish to mark some
data as volatile. That is in the event of memory pressure the kernel is
free to discard such buffers safe in the knowledge that the application
can recreate them on demand, and is simply using these as a cache.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:43:31 -07:00
Chris Wilson
31169714fc drm/i915: Register a shrinker to free inactive lists under memory pressure
This should help GEM handle memory pressure sitatuions more gracefully.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:43:31 -07:00
Chris Wilson
725ceaa08a drm/i915: Include buffer size and dirty state in debugfs lists
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:43:30 -07:00
Chris Wilson
e67b8ce1b5 drm/i915: Remove stored gtt_alignment
There is no need to store the gtt_alignment as it is either explicitly
set according to the hardware requirements (e.g. scanout) or the
minimum alignment is computed on demand.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:43:29 -07:00
Chris Wilson
4960aaca14 drm/i915: Add buffer to inactive list immediately during fault
If we failed to set the domain, the buffer was no longer being tracked
on any list.

Cc: stable@kernel.org
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:43:28 -07:00
Jesse Barnes
c1a1cdc159 drm/i915: fix startup hang on some non-mobile platforms
Due to a bogus FBC support check and failing to check for FBC support
in the right places, mode setting on non-mobile platforms could fail
and hang in the FBC disable routine.  Fix it up.

This fix highlights the need for cleanups in this area (function
pointers and better feature support checks).  Patches for that to
follow.

Tested-by: Kenny Graunke <kenny@whitecape.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:43:27 -07:00
Jesse Barnes
06891e27a9 drm/i915: fix suspend/resume breakage in lid notifier
We now unconditionally restore the mode at lid open time since some
platforms turn off the panel, pipes or other display elements when the
lid is closed.  There's a problem with doing this at resume time
however.

At resume time, we'll get a lid event, but restoring the mode at that
time may not be safe (e.g. if we get the lid event before global state
has been restored), so check the suspended state and make sure our
restore is locked against other mode updates.

Tested-by: Ben Gamari <bgamari.foss@gmail.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:42:54 -07:00
Ben Gamari
ba1234d17b drm/i915: Make dev_priv->mm.wedged an atomic_t
There is a very real possibility that multiple CPUs will notice that the
GPU is wedged. This introduces all sorts of potential race conditions.
Make the wedged flag atomic to mitigate this risk.

Signed-off-by: Ben Gamari <bgamari.foss@gmail.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:36:46 -07:00
Ben Gamari
f316a42cc4 drm/i915: Hookup chip reset in error handler
This patch uses the previously introduced chip reset logic to reset the
chip when an error event is detected.

Signed-off-by: Ben Gamari <bgamari.foss@gmail.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:36:30 -07:00
Ben Gamari
11ed50ec2a drm/i915: Implement GPU reset on i965
This patch puts in place the machinery to attempt to reset the GPU. This
will be used when attempting to recover from a GPU hang.

Signed-off-by: Owain G. Ainsworth <oga@openbsd.org>
Signed-off-by: Ben Gamari <bgamari.foss@gmail.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:36:22 -07:00
Ben Gamari
f65d94211e drm/i915: Add hangcheck timer
We set a periodic timer to check on the GPU, resetting it every time a
batch is completed. If the timer elapses, we check acthd. If acthd
hasn't changed in two timer periods, we assume the chip is wedged.

This is implemented in such a way that it leaves the option open to
employ adaptive timer intervals in the future. One could wait until
several timer periods have elapsed before declaring the chip dead. If
the chip comes back after several periods but before the "dead"
threshold, the timer interval or dead threshold could be raised.

It is important to note that while checking for active requests, we need
to account for the fact that requests are removed from the list (i.e.
retired) in a deferred work queue handler. This means that merely
checking for an empty request_list is insufficient; the list could be
non-empty yet the GPU still idle, causing the hangcheck timer to
incorrectly mark the GPU as wedged (it took me a while to figure that
out---sigh...)

Signed-off-by: Ben Gamari <bgamari.foss@gmail.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:36:01 -07:00
Ben Gamari
22be172423 drm/i915: make i915_seqno_passed non-static
We'll need it in i915_irq.c for checking whether there are outstanding
requests. Also, the function really ought to return a bool, not an int.

Signed-off-by: Ben Gamari <bgamari.foss@gmail.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:35:11 -07:00
Ben Gamari
1341d655dd drm/i915: Refactor save/restore code
We move the display-specific code into it's own functions, called
from the general GPU state save/restore functions. This will be needed
later by the GPU reset code.

Signed-off-by: Ben Gamari <bgamari.foss@gmail.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:34:27 -07:00
Ben Gamari
ffed1d0920 drm/i915: Check whether chip is wedged in i915_wait_request()
i915_wait_request() only checks mm.wedged after it interacts with the
hardware, generally causing the driver to lock up waiting for a wedged
chip. Make sure we check mm.wedged as the first thing we do.

Reported-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ben Gamari <bgamari.foss@gmail.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:33:52 -07:00
Li Peng
078a033f45 drm/i915: fix opregion backlight chip detect and range
BLC_PWM_CTL2 is for 965+ only, so add device model check for
legacy backlight control.

For native backlight control, it maps the backlight value (0~255)
in opregion ASLE[BCLP] to backlight duty cycle (0~max_backlight)
and set into control register.

It also add support for IGD device, which follows opregion spec.

Signed-off-by: Li Peng <peng.li@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:32:08 -07:00
Zhenyu Wang
8dd81a381e drm/i915: Fix LVDS panel fitting on Arrandale
Arrandale has new window based method for panel fitting.
This one enables full screen aspect scaling on LVDS. It fixes
standard mode display failure on LVDS for Arrandale.

Cc: Stable Team <stable@kernel.org>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:31:10 -07:00
Zhenyu Wang
730915d65f drm/i915: Remove DAC disable in CRT force detect on IGDNG
This is not required on newer stepping hardware to get
reliable force detect status. Removing this fixes screen
blank flicker in CRT detect on IGDNG.

Cc: Stable Team <stable@kernel.org>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:31:06 -07:00
Zhenyu Wang
339e5a4c78 drm/i915: Fix SSC frequence for IGDNG
IGDNG LVDS SSC uses 120Mhz freq. This fixes one
1600x900 LVDS panel black issue on IGDNG with SSC enabled.

Cc: Stable Team <stable@kernel.org>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:31:01 -07:00
Zhenyu Wang
b09aea7fb3 drm/i915: Fix typo for wrong LVDS clock setting on IGDNG
New register for PCH LVDS on IGDNG should be used.
This is a copy-n-paste typo. This fixes possible dual
channel LVDS panel failure on IGDNG.

Cc: Stable Team <stable@kernel.org>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:30:14 -07:00
Jesse Barnes
6f465a8925 drm/i915: fix typo in compressed buffer setup
We want the compressed line length buffer address, not the framebuffer
address.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17 14:22:44 -07:00
Chris Wilson
7e61615857 drm/i915: Only destroy a constructed mmap offset
drm_ht_remove_item() does not handle removing an absent item and the hlist
in particular is incorrectly initialised. The easy remedy is simply skip
calling i915_gem_free_mmap_offset() unless we have actually created the
offset and associated ht entry.

This also fixes the mishandling of a partially constructed offset which
leaves pointers initialized after freeing them along the
i915_gem_create_mmap_offset() error paths.

In particular this should fix the oops found here:
https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/415357/comments/8

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Eric Anholt <eric@anholt.net>
Cc: stable@kernel.org
2009-09-11 11:40:39 -07:00
Eric Anholt
e517a5e970 agp/intel: Fix the pre-9xx chipset flush.
Ever since we enabled GEM, the pre-9xx chipsets (particularly 865) have had
serious stability issues.  Back in May a wbinvd was added to the DRM to
work around much of the problem.  Some failure remained -- easily visible
by dragging a window around on an X -retro desktop, or by looking at bugzilla.

The chipset flush was on the right track -- hitting the right amount of
memory, and it appears to be the only way to flush on these chipsets, but the
flush page was mapped uncached.  As a result, the writes trying to clear the
writeback cache ended up bypassing the cache, and not flushing anything!  The
wbinvd would flush out other writeback data and often cause the data we wanted
to get flushed, but not always.  By removing the setting of the page to UC
and instead just clflushing the data we write to try to flush it, we get the
desired behavior with no wbinvd.

This exports clflush_cache_range(), which was laying around and happened to
basically match the code I was otherwise going to copy from the DRM.

Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Brice Goglin <Brice.Goglin@ens-lyon.org>
Cc: stable@kernel.org
2009-09-11 11:39:23 -07:00
Jesse Barnes
8082400327 drm/i915: framebuffer compression for pre-GM45
This patch adds framebuffer compression (good for about ~0.5W power
savings in the best case) support for pre-GM45 chips.  GM45+ have a new,
more flexible FBC scheme that will be added in a separate patch.

FBC can't always be enabled: the compressed buffer must be physically
contiguous and reside in stolen space.  So if you have a large display
and a small amount of stolen memory, you may not be able to take
advantage of FBC.  In some cases, a BIOS setting controls how much
stolen space is available.  Increasing this to 8 or 16M can help.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
2009-09-10 19:46:07 -07:00
Jesse Barnes
06324194ee drm/i915: generate a KMS uevent at lid open/close time
With all the other lid pieces in place, it's easy to generate a uevent
for the LVDS connector just like we do for other outputs.  Should make
lid open/close fit in with the rest of a userland based output
reconfiguration scheme.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
2009-09-10 16:10:31 -07:00
Jesse Barnes
b42d4c5c6a drm/i915: use ACPI LID status for LVDS ->detect hook
We can't load or hotplug detect LVDS like we can other outputs, but if
there's a lid device present we can use it as a proxy.  This allows the
LFP state to be determined at ->detect time, making configurations
requiring manual intervention today "just work" assuming the lid device
status is correct.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
2009-09-10 16:10:21 -07:00
Jesse Barnes
c1c7af6089 drm/i915: force mode set at lid open time
Some laptop platforms will disable pipes and/or planes at lid close time
and not restore them when the lid is opened again.  So catch the lid
event, and if the lid was opened, force a mode restore.

Fixes fdo bug #21230.

Acked-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
2009-09-10 16:10:00 -07:00
Jesse Barnes
7e12715ecc ACPI button: provide lid status functions
Some drivers need to know when a lid event occurs and get the current
status.  This can be useful for when a platform firmware clobbers some
hardware state at lid time, and a driver needs to restore things when
the lid is opened again.

Acked-by: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
2009-09-10 16:09:11 -07:00
Li Peng
af729a26cc Add G33 series in VGA hotplug support category
Test on the IGD chip, which is a G33-like graphic device.

Signed-off-by: Li Peng <peng.li@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
2009-09-10 11:32:49 -07:00
Zhao Yakui
bb66c5122b drm/i915: Write zero to DPLL_MD Reg for non-SDVO output
When the output device is LVDS, maybe the pixel clock of adjusted_mode will be
less than that in mode. In such case it will set the incorrect multipler factor
in DPLL_MD register.
So the dpll_md_reg will be reset when the output type is non-SDVO

https://bugs.freedesktop.org/show_bug.cgi?id=22761

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Reviewd-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Eric Anholt <eric@anholt.net>
2009-09-10 11:31:04 -07:00
Zhao Yakui
e270846fa7 drm/i915: Add the missing clone_mask for SDVO-VGA(RGB1)
Add the missing clone_mask for SDVO-VGA(RGB1)

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
2009-09-10 11:30:54 -07:00
Zhao Yakui
d0cbde93cc drm/i915: Add the brightness property for SDVO-LVDS
When the sdvo device is detected as SDVO-LVDS, we will check whether the
brightness is supported by issue SDVO enhancement command.
If it is supported, we will add the brightness property and then brightness
can be adjusted.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
2009-09-10 11:30:32 -07:00
Zhao Yakui
b9219c5e8b drm/i915: Add the enhancement property for SDVO-TV
When the sdvo device is detected as SDVO-TV, we will check whether the
sepecific picture enhancement is supported. If it is supported, we will
add the corresponnding property for SDVO-TV. We will add the following
property for the SDVO-TV enhancements if they are supported:
 * Contrast/Brightness/Saturation/Hue.
 * left/right/top/bottom margin: This is implemented by using the
   horizontal/vertical overscan enhancements. When the overscan
   enhancements are supported, the above properties will be added. This is
   to be compatible with what we have done in integrated-TV.
 * horizontal pos/vertical pos.

http://bugs.freedesktop.org/show_bug.cgi?id=22891

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
2009-09-10 11:28:57 -07:00
Eric Anholt
5323fd042f drm/i915: Zap mmaps of objects before unbinding them from the GTT.
Otherwise, some other userland writing into its buffer may race to land
writes either after the CPU thinks it's got a coherent view, or after its
GTT entries have been redirected to point at the scratch page.  Either
result is unpleasant.

Signed-off-by: Eric Anholt <eric@anholt.net>
2009-09-09 12:52:05 -07:00