Now that framebuffer are reference-counted for all use-sites, update
the documentation accordingly to stress the new rules for
initialization and teardown.
Also add a short paragraph about the implications for drivers of the
new locking rules.
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
The coup de grace of the entire journey. No more dropped frames every
10s on my testbox!
I've tried to audit all ->detect and ->get_modes callbacks, but things
became a bit fuzzy after trying to piece together the umpteenth
implemenation. Afaict most drivers just have bog-standard output
register frobbing with a notch of i2c edid reading, nothing which
could potentially race with the newly concurrent pageflip/set_cursor
code. The big exception is load-detection code which requires a
running pipe, but radeon/nouveau seem to to this without touching any
state which can be observed from page_flip (e.g. disabled crtcs
temporarily getting enabled and so a pageflip succeeding).
The only special case I could find is the i915 load detect code. That
uses the normal modeset interface to enable the load-detect crtc, and
so userspace could try to squeeze in a pageflip on the load-detect
pipe. So we need to grab the relevant crtc mutex in there, to avoid
the temporary crtc enabling to sneak out and be visible to userspace.
Note that the sysfs files already stopped grabbing the per-crtc locks,
since I didn't want to bother with doing a interruptible
modeset_lock_all. But since there's very little in-between breakage
(essentially just the ability for userspace to pageflip on load-detect
crtcs when it shouldn't on the i915 driver) I figured I don't need to
bother.
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
The pagelip ioctl itself is rather simply, so the hard work for this
patch is auditing all the drivers:
- exynos: Pageflip is protect with dev->struct_mutex and ...
synchronous. But nothing fancy going on, besides a check whether the
crtc is enabled, which should probably be somewhere in the drm core
so that we have unified behaviour across all drivers.
- i915: hw-state is protected with dev->struct_mutex, the delayed
unpin work together with the other stuff the pageflip complete irq
handler needs is protected by the event_lock spinlock.
- nouveau: With the pin/unpin functions fixed, everything looks safe:
A bit of ttm wrestling and refcounting, and a few channel accesses.
The later are either already proteced sufficiently, or are now safe
with the channel locking introduced to make cursor updates safe.
- radeon: The irq_get/put functions look a bit race, since the
atomic_inc/dec isn't protect with locks. Otoh they're all per-crtc,
so we should be safe with per-crtc locking from the drm core. Then
there's tons of per-crtc register access, which could potentially go
through the indirect reg acces. But that's fixed to make cursor
updates concurrent. Bookeeping for the drm even is also protected
with the even_lock, which also protects against the pageflip irq
handler since radeon hw seems to have no way to queue these up
asynchronously. Otherwise just a bit of ttm-based buffer handling
and fencing, which is now safe with the previous patch to hold
bdev->fence_lock while grabbing the ttm fence.
- shmob: Only one crtc. That's an easy one ...
- vmwgfx: As usual a bit special with tons different things:
- Flippable check using is_implicit and num_implicit. Changes to
those seem to be nicely covered with the global modeset lock, so
we should be fine.
- Some dirty cliprect handling stuff, or at least that is my guess.
Looks like it's fine since either it's per-crtc, invariant or
(like the execbuf stuff launched) protected otherwise.
- Adding the actual flip to the fence_event list. On a quick look
this seems to have solid locking in place, too.
... but generally this is all way over my head.
- imx: Impressive display of races between the page_flip
implementation and the irq handler. Also, ipu_drm_set_base which
gets eventually called from the irq handler to update the display
base isn't really protected against concurrent set_config calls from
process context. In any case, going for per-crtc locking won't make
this worse, so nothing to do.
- omap: The new async callback code merged into 3.8 seems to have
solid locking in place, and there doesn't seem to be any shared
state at risk. Especially since the callbacks still use
modeset_lock_all and are so not converted.
v2: Update omapdrm analysis to 3.8 code per the discussion with Rob
Clark.
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Now that all framebuffer usage is properly refcounted, we are no
longer required to hold the modeset locks while dropping the last
reference. Hence implemented a fastpath which avoids the potential
stalls associated with grabbing mode_config.lock for the case where
there's no other reference around.
Explain in a big comment why it is safe. Also update kerneldocs with
the new locking rules around drm_framebuffer_remove.
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Afact vmwgfx already has all the right refcounting implemented on the
backing storage, and we only need to ensure that the drm fb doesn't
disappear untimely. So holding onto the fb reference from _lookup
until vmw_kms_present has completed should be enough.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
With the prep patch to encapsulate ->set_crtc calls, this is now
rather easy. Hooray for inconsistent semantics between ->set_crtc and
->page_flip, where the driver callback is supposed to update the fb
pointer, and ->update_plane, where the drm core does the same.
Also, since the drm core functions check crtc->fb before calling into
driver callbacks, we can't really reduce the critical sections
protected by the mode_config locks.
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Now plane->fb holds a reference onto it's framebuffer. Nothing too
fancy going on here:
- Extract __drm_framebuffer_unreference to be called when we know
we're not dropping the last reference, e.g. useful in the fb cleanup
code.
- Reduce the locked sections in the set_plane ioctl to only protect
plane->fb/plane->crtc and the driver callback (i.e. hw state).
Everything either doesn't disappear (crtc, plane) or is refcounted
(fb), and all the data we check is invariant over the respective
object's lifetimes.
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
We only need to ensure that the fb stays around for long enough. While
at it, only grab the modeset locks when we need them (since most
drivers don't implement the dirty callback, this should help jitter
and stalls when using the generic modeset driver).
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
We only need to push the fb unreference a bit down. While at it,
properly pass the return value from ->create_handle back to userspace.
Most drivers either return -ENODEV if they don't have a concept of
buffer objects (ast, cirrus, ...) or just install a handle for the
underlying gem object (which is ok since we hold a reference on that
through the framebuffer).
v2: Split out the ->create_handle rework in the individual drivers.
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
And drop it where it's not needed. Most driver just lookup the gem
object, allocate an fb struct, fill in all the useful fields and then
register it with drm_framebuffer_init.
All of these operations are already separately locked, and since we
only put the fb into the fpriv->fbs list _after_ having called
->fb_create, we can't also race with rmfb. We can otoh race with other
ioctls that put the framebuffer to use, but all drivers have been
reorganized already to call drm_framebuffer_init last in the fb
creation sequence.
So essentially, we can completely remove any modeset locks from the
addfb ioctl paths. Yeah!
Also, reference-counting is solid - we get a reference from fb_create
which we transfer to the fpriv->fbs list. And after unlocking the
fpriv->fbs_lock we don't touch the framebuffer any longer. Furthermore
drm_framebuffer_init has added a 2nd reference for the idr lookup, and
any access through that table will do it's own refcounting.
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Atm we still need to unconditionally take the modeset locks in the
rmfb paths. But eventually we only want to take them if there are
other users around as a slow-path. This way sane userspace avoids
blocking on edid reads and other stuff in rmfb if it ensures that the
fb isn't used anywhere by a crtc/plane.
We can do a quick check for such other users once framebuffers are
properly refcounting by locking at the refcount - if it's more than 1,
there are other users left. Again, rmfb racing against other ioctls
isn't a real problem, userspace is allowed to shoot its foot.
This patch just prepares this by moving the modeset locks to nest
within fpriv->fbs_lock. Now the distinction between the fbs_lock and
the device-global fb_lock is clear, since we need to hold the fbs_lock
outside of any modeset_locks in fb_release.
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Since otherwise looking and reference-counting around
drm_framebuffer_lookup will be an unmanageable mess. With this change,
an object can either be found in the idr and will stay around once we
incremented the reference counter. Or it will be gone for good and
can't be looked up using its id any more.
Atomicity is guaranteed by the dev->mode_config.fb_lock. The
newly-introduce fpriv->fbs_lock looks a bit redundant, but the next
patch will shuffle the locking order between these two locks and all
the modeset locks taken in modeset_lock_all, so we'll need it.
Also, since userspace could do really funky stuff and race e.g. a
getresources with an rmfb, we need to make sure that the kernel
doesn't fall over trying to look-up an inexistent fb, or causing
confusion by having two fbs around with the same id. Simply reset the
framebuffer id to 0, which marks it as reaped. Any lookups of that id
will fail, so the object is really gone for good from userspace's pov.
Note that we still need to protect the "remove framebuffer from all
use-cases" and the final unreference with the modeset-lock, since most
framebuffer use-sites don't implement proper reference counting yet.
We can only lift this once _all_ users are converted.
With this change, two references are held on alife, but unused
framebuffers:
- The reference for the idr lookup, created in this patch.
- For user-created framebuffers the fpriv->fbs reference, for
driver-private fbs the driver is supposed to hold it's own last
reference.
Note that the dev->mode_config.fb_list itself does _not_ hold a
reference onto the framebuffers (this list is essentially only used
for debugfs files). Hence if there's anything left there when the
driver has cleaned up all it's modeset resources, this is a ref-leak.
WARN about it.
Now we only need to fix up all other places to properly reference
count framebuffers.
v2: Fix spelling fail in a comment spotted by Rob Clark.
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
We have two classes of framebuffer
- Created by the driver (atm only for fbdev), and the driver holds
onto the last reference count until destruction.
- Created by userspace and associated with a given fd. These
framebuffers will be reaped when their assoiciated fb is closed.
Now these two cases are set up differently, the framebuffers are on
different lists and hence destruction needs to clean up different
things. Also, for userspace framebuffers we remove them from any
current usage, whereas for internal framebuffers it is assumed that
the driver has done this already.
Long story short, we need two different ways to cleanup such drivers.
Three functions are involved in total:
- drm_framebuffer_remove: Convenience function which removes the fb
from all active usage and then drops the passed-in reference.
- drm_framebuffer_unregister_private: Will remove driver-private
framebuffers from relevant lists and drop the corresponding
references. Should be called for driver-private framebuffers before
dropping the last reference (or like for a lot of the drivers where
the fbdev is embedded someplace else, before doing the cleanup
manually).
- drm_framebuffer_cleanup: Final cleanup for both classes of fbs,
should be called by the driver's ->destroy callback once the last
reference is gone.
This patch just rolls out the new interfaces and updates all drivers
(by adding calls to drm_framebuffer_unregister_private at all the
right places)- no functional changes yet. Follow-on patches will move
drm core code around and update the lifetime management for
framebuffers, so that we are no longer required to keep framebuffers
alive by locking mode_config.mutex.
I've also updated the kerneldoc already.
vmwgfx seems to again be a bit special, at least I haven't figured out
how the fbdev support in that driver works. It smells like it's
external though.
v2: The i915 driver creates another private framebuffer in the
load-detect code. Adjust its cleanup code, too.
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
And replace all fb lookups with it. Also add a WARN to
drm_mode_object_find since that is now no longer the blessed interface
to look up an fb. And add kerneldoc to both functions.
This only updates all callsites, but immediately drops the acquired
refence again. Hence all callers still rely on the fact that a mode fb
can't disappear while they're holding the struct mutex. Subsequent
patches will instate proper use of refcounts, and then rework the rmfb
and unref code to no longer serialize fb destruction with the
mode_config lock. We don't want that since otherwise a compositor
might end up stalling for a few frames in rmfb.
v2: Don't use kref_get_unless_zero - Greg KH doesn't like that kind of
interface.
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Well, at least step 1. The goal here is that framebuffer objects can
survive outside of the mode_config lock, with just a reference held
as protection. The first step to get there is to introduce a special
fb_lock which protects fb lookup, creation and destruction, to make
them appear atomic.
This new fb_lock can nest within the mode_config lock. But the idea is
(once the reference counting part is completed) that we only quickly
take that fb_lock to lookup a framebuffer and grab a reference,
without any other locks involved.
vmwgfx is the only driver which does framebuffer lookups itself, also
wrap those calls to drm_mode_object_find with the new lock.
Also protect the fb_list walking in i915 and omapdrm with the new lock.
As a slight complication there's also the list of user-created fbs
attached to the file private. The problem now is that at fclose() time
we need to walk that list, eventually do a modeset call to remove the
fb from active usage (and are required to be able to take the
mode_config lock), but in the end we need to grab the new fb_lock to
remove the fb from the list. The easiest solution is to add another
mutex to protect this per-file list.
Currently that new fbs_lock nests within the modeset locks and so
appears redudant. But later patches will switch around this sequence
so that taking the modeset locks in the fb destruction path is
optional in the fastpath. Ultimately the goal is that addfb and rmfb
do not require the mode_config lock, since otherwise they have the
potential to introduce stalls in the pageflip sequence of a compositor
(if the compositor e.g. switches to a fullscreen client or if it
enables a plane). But that requires a few more steps and hoops to jump
through.
Note that framebuffer creation/destruction is now double-protected -
once by the fb_lock and in parts by the idr_lock. The later would be
unnecessariy if framebuffers would have their own idr allocator. But
that's material for another patch (series).
v2: Properly initialize the fb->filp_head list in _init, otherwise the
newly added WARN to check whether the fb isn't on a fpriv list any
more will fail for driver-private objects.
v3: Fixup two error-case unlock bugs spotted by Richard Wilbur.
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
->cursor_move uses mostly the same facilities in drivers as
->cursor_set, so pretty much nothing to fix up:
- ast/gma500/i915: They all use per-crtc registers to update the
cursor position. ast again touches the global cursor cache, but
that's ok since there's only one crtc.
- nouveau: nv50+ is again special, updates happen through the per-crtc
channel (without pushbufs), so it's not protected by the new evo
lock introduced earlier. But since this channel is per-crtc, we
should be fine anyway.
- radeon: A bit a mess: avivo asics need a workaround when both output
pipes are enabled, which means it'll access the crtc list. Just
reading that flag is ok though as long as radeon _always_ grabs all
locks when changing the crtc configuration. Which means with the
current scheme it cannot do an optimized modeset which only locks
the relevant crtcs. This can be fixed though by introducing a bit of
global state with separate locks and ensure in the modeset code that
the cursor will be updated appropriately when enabling the 2nd pipe
(on affected asics).
- vmwgfx: I still don't understand what it's doing exactly, so apply
the same trick for now.
v2: Fixup unlocking for the error cases, spotted by Richard Wilbur.
v3: Another error-case fixup.
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
First convert ->cursor_set to only take the crtc lock, since that
seems to be the function with the least amount of state - the core
ioctl function doesn't check anything which can change at runtime, so
we don't have any object lifetime issues to contend.
The only thing which is important is that the driver's implementation
doesn't touch any state outside of that single crtc which is not yet
properly protected by other locking:
- ast: access the global ast->cache_kmap. Luckily we only have on crtc
on this driver, so this is fine. Add a comment.
- gma500: calls gma_power_begin|and and psb_gtt_pin|unpin, both which
have their own locking to protect their state. Everything else is
crtc-local.
- i915: touches a bit of global gem state, all protected by the One
Lock to Rule Them All (dev->struct_mutex).
- nouveau: Pre-nv50 is all nice, nv50+ uses the evo channels to queue
up all display changes. And some of these channels are device
global. But this is fine now since the previous patch introduced an
evo channel mutex.
- radeon: Uses some indirect register access for cursor updates, but
with the previous patches to protect these indirect 2-register
access patterns with a spinlock, this should be fine now, too.
- vmwgfx: I have no idea how that works - update_cursor_position
doesn't take any per-crtc argument and I haven't figured out any
other place where this could be set in some form of a side-channel.
But vmwgfx definitely has more than one crtc (or at least can
register more than one), so I have no idea how this is supposed to
not fail with the current code already. Hence take the easy way out
and simply acquire all locks (which requires dropping the crtc lock
the core acquired for us). That way it's not worse off for
consistency than the old code.
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
*drumroll*
The basic idea is to protect per-crtc state which can change without
touching the output configuration with separate mutexes, i.e. all the
input side state to a crtc like framebuffers, cursor settings or plane
configuration. Holding such a crtc lock gives a read-lock on all the
other crtc state which can be changed by e.g. a modeset.
All non-crtc state is still protected by the mode_config mutex.
Callers that need to change modeset state of a crtc (e.g. dpms or
set_mode) need to grab both the mode_config lock and nested within any
crtc locks.
Note that since there can only ever be one holder of the mode_config
lock we can grab the subordinate crtc locks in any order (if we need
to grab more than one of them). Lockdep can handle such nesting with
the mutex_lock_nest_lock call correctly.
With this functions that only touch connectors/encoders but not crtcs
only need to take the mode_config lock. The biggest such case is the
output probing, which means that we can now pageflip and move cursors
while the output probe code is reading an edid.
Most cases neatly fall into the three buckets:
- Only touches connectors and similar output state and so only needs
the mode_config lock.
- Touches the global configuration and so needs all locks.
- Only touches the crtc input side and so only needs the crtc lock.
But a few cases that need special consideration:
- Load detection which requires a crtc. The mode_config lock already
prevents a modeset change, so we can use any unused crtc as we like
to do load detection. The only thing to consider is that such
temporary state changes don't leak out to userspace through ioctls
that only take the crtc look (like a pageflip). Hence the load
detect code needs to grab the crtc of any output pipes it touches
(but only if it touches state used by the pageflip or cursor
ioctls).
- Atomic pageflip when moving planes. The first case is sane hw, where
planes have a fixed association with crtcs - nothing needs to be
done there. More insane^Wflexible hw needs to have plane->crtc
mapping which is separately protect with a lock that nests within
the crtc lock. If the plane is unused we can just assign it to the
current crtc and continue. But if a plane is already in use by
another crtc we can't just reassign it.
Two solution present themselves: Either go back to a slow-path which
takes all modeset locks, potentially incure quite a hefty delay. Or
simply disallowing such changes in one atomic pageflip - in general
the vblanks of two crtcs are not synced, so there's no sane way to
atomically flip such plane changes accross more than one crtc. I'd
heavily favour the later approach, going as far as mandating it as
part of the ABI of such a new a nuclear pageflip.
And if we _really_ want such semantics, we can always get them by
introducing another pageflip mutex between the mode_config.mutex and
the individual crtc locks. Pageflips crossing more than one crtc
would then need to take that lock first, to lock out concurrent
multi-crtc pageflips.
- Optimized global modeset operations: We could just take the
mode_config lock and then lazily lock all crtc which are affected by
a modeset operation. This has the advantage that pageflip could
continue unhampered on unaffected crtc. But if e.g. global resources
like plls need to be reassigned and so affect unrelated crtcs we can
still do that - nested locking works in any order.
This patch just adds the locks and takes them in drm_modeset_lock_all,
no real locking changes yet.
v2: Need to initialize the new lock in crtc_init and lock it righ
away, for otherwise the modeset_unlock_all below will try to unlock a
not-locked mutex.
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
I've left the locking in the debugfs code as-is, it's essentially just
used to keep the framebuffer object alive (which won't be necessary
any more later on). We don't need fb refcounting either, since the new
mode_config.fb_lock ensures that the framebuffers can't disappear
(once mode_config.mutex doesn't guarantee this any more later on in
the series).
The fbcon restore needs all modeset locks. The crtc callbacks seem to
only need the crtc locks, but I've quickly discussed things with Rob
Clark and he's fine with just using modeset_lock_all for those, too.
He'll look into converting things over later.
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Ok, this one here is a bit more complicated, and I can't really claim
to fully understand the locking and lifetime rules of the vmwgfx
driver. So just convert ever mutex_lock call, including the
interruptible one. Since other places (e.g. in the execbuf ioctl) take
the mode_config.mutex without bothering with interruptible handling,
I've figured I should be able to get away with this in a few more
places ...
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Only two places:
- suspend/resume
- Some really strange mode validation tool with too much funny-lucking
hand-rolled conversion code.
- The recently-added lastclose fbdev restore code.
Better safe than sorry, so convert both places to keep the locking
semantics as much as possible.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Two exceptions:
- debugfs files only read information which is not related to crtc, so
can stay on the modeset_config lock.
- Same holds for the edp vdd work in intel_dp.c. Add a corresponding
WARN_ON and a comment next to the intel_dp struct fields for
documentation.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This is the first step towards introducing the new modeset locking
scheme. The plan is to put helper functions into place at all the
right places step-by-step, so that the final patch to switch on the
new locking scheme doesn't need to touch every single driver.
This helper here will serve as the shotgun solutions for all places
where a more fine-grained locking isn't (yet) implemented.
v2: Fixup kerneldoc for unlock_all.
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
With refcounting we need to adjust framebuffer refcounts at each
callsite - much easier to do if they all call the same little helper
function.
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Some drivers don't have real ->create_handle callbacks.
- cirrus/ast/mga200: Returns either 0 or -EINVAL.
- udl: Didn't even bother with a callback, leading to a nice
userspace-triggerable OOPS.
- vmwgfx: This driver bothered with an implementation to return 0 as
the handle (which is the canonical no-obj gem handle).
All have in common that ->create_handle doesn't really make too much
sense for them - that ioctl is used only for seamless fb takeover in
the radeon/nouveau/i915 ddx drivers. So allow drivers to not implement
this and return a consistent -ENODEV.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
... by moving the bo_pin/bo_unpin manipulation of the pin_refcount
under the protection of the ttm reservation lock. pin/unpin seems
to get called from all over the place, so atm this is completely racy.
After this patch there are only a few places in cleanup functions
left which access ->pin_refcount without locking. But I'm hoping that
those are safe and some other code invariant guarantees that this
won't blow up.
In any case, I only need to fix up pin/unpin to make ->pageflip work
safely, so let's keep it at that.
Add a comment to the header to explain the new locking rule.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
With per-crtc locks modeset operations can run in parallel, and the
cursor code uses the device-global evo master channel for hw frobbing.
But the pageflip code can also sync with the master under some
circumstances. Hence just wrap things up in a mutex to ensure that
pushbuf access doesn't intermingle.
The approach here is a bit overkill since the per-crtc channels used
to schedule the pageflips could probably be used without this pushbuf
locking, but I'm not familiar enough with the nouveau codebase to be
sure of that.
v2: Add missing mutex_init to avoid angering lockdep.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Doing this within the fb->destroy callback leads to a locking
nightmare. And all other drm drivers that restore the fbcon do
it in lastclose, too.
With this adjustments all fb->destroy callbacks optionally drop
references to any gem objects used as backing storage, call
drm_framebuffer_cleanup and then kfree the struct. Which nicely
simplifies the locking for framebuffer unreferencing and freeing,
since this doesn't require that we hold the mode_config lock. A
slight exception is the vmwgfx surface backed framebuffer, it also
calls drm_master_put and removes the object from a device-private
framebuffer list. Both seem to have solid locking in place already.
Conclusion is that now it is no longer required to hold the
mode_config lock while freeing a framebuffer.
v2: Drop the corresponding mutex_lock WARN check from
drm_framebuffer_unreference.
v3: Use just the mode_config lock not modeset_lock_all, due to patch
reordering.
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
vmwgfx has an oddity, when failing to reference the surface it'll
return 0, since that's what the successfull drm_framebuffer_init will
leave behind in ret. Fix this up by returning -EINVAL.
Split out from all the other driver updates due to the above tiny
semantic change. Shouldn't matter though since the reference grabbing
seemingly can't fail.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
With more fine-grained locking we can no longer rely on the big
mode_config lock to prevent concurrent access to mode resources
like framebuffers. Instead a framebuffer becomes accessible to
other threads as soon as it is added to the relevant lookup
structures. Hence it needs to be fully set up by the time drivers
call drm_framebuffer_init.
This patch here is the drivers part of that reorg. Nothing really fancy
going on safe for three special cases.
- exynos needs to be careful to properly unref all handles.
- nouveau gets a resource leak fixed for free: one of the error
cases didn't cleanup the framebuffer, which is now moot since
the framebuffer is only registered once it is fully set up.
- vmwgfx requires a slight reordering of operations, I'm hoping I didn't
break anything (but it's refcount management only, so should be safe).
v2: Split out exynos, since it's a bit more hairy than expected.
v3: Drop bogus cirrus hunk noticed by Richard Wilbur.
v4: Split out vmwgfx since there's a small change in return values.
Reviewed-by: Rob Clark <rob@ti.com> (core + omapdrm)
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
And do a quick pass to adjust them to the last few (years?) of changes
...
This time actually compile-tested ;-)
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
- config_cleanup was confused: It claimed that callers need to hold
the modeset lock, but the connector|encoder_cleanup helpers grabbed
that themselves (note that crtc_cleanup did _not_ grab the modeset
lock). Which resulted in all drivers _not_ hodling the lock. Since
this is for single-threaded cleanup code, drop the requirement from
docs and also drop the lock_grabbing from all _cleanup functions.
- Kill the LOCKING section in the doctype, since clearly we're not
good enough to keep them up-to-date. And misleading locking
documentation is worse than useless (see e.g. the comment in the
vmgfx driver about the cleanup mess). And since for most functions
the very first line either grabs the lock or has a WARN_ON(!locked)
the documentation doesn't really add anything.
- Instead put in some effort into explaining the only two special
cases a bit better: config_init and config_cleanup are both called
from single-threaded setup/teardown code, so don't do any locking.
It's the driver's job though to enforce this.
- Where lacking, add a WARN_ON(!is_locked). Not many places though,
since locking around fbdev setup/teardown is through-roughly screwed
up, and so will break almost every single WARN annotation I've tried
to add.
- Add a drm_modeset_is_locked helper - the Grate Modset Locking Rework
will use the compiler to assist in the big reorg by renaming the
mode lock, so start encapsulating things. Unfortunately this ended
up in the "wrong" header file since it needs the definition of
struct drm_device.
v2: Drop most WARNS again - we hit them all over the place, mostly in
the setup and teardown sequences. And trying to fix it up leads to
nice deadlocks, since the locking in the setup code is really
inconsistent.
Reviewed-by: Rob Clark <rob@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Pull more s390 patches from Martin Schwidefsky:
"A couple of bug fixes: one of the transparent huge page primitives is
broken, the sched_clock function overflows after 417 days, the XFS
module has grown too large for -fpic and the new pci code has broken
normal channel subsystem notifications."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/chsc: fix SEI usage
s390/time: fix sched_clock() overflow
s390: use -fPIC for module compile
s390/mm: fix pmd_pfn() for thp
- fix(es) for compound buffers
- fix for dquot soft timer asserts due to overflow of d_blk_softlimit
- fix for regression in dir v2 code introduced in commit 20f7e9f3
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Merge tag 'for-linus-v3.8-rc4' of git://oss.sgi.com/xfs/xfs
Pull xfs bugfixes from Ben Myers:
- fix(es) for compound buffers
- fix for dquot soft timer asserts due to overflow of d_blk_softlimit
- fix for regression in dir v2 code introduced in commit 20f7e9f372
("xfs: factor dir2 block read operations")
* tag 'for-linus-v3.8-rc4' of git://oss.sgi.com/xfs/xfs:
xfs: recalculate leaf entry pointer after compacting a dir2 block
xfs: remove int casts from debug dquot soft limit timer asserts
xfs: fix the multi-segment log buffer format
xfs: fix segment in xfs_buf_item_format_segment
xfs: rename bli_format to avoid confusion with bli_formats
xfs: use b_maps[] for discontiguous buffers
* cpuidle initialization regression fix from Krzysztof Mazur.
* cpuidle fix for power usage fields handling from Daniel Lezcano.
* ACPI build fix from Yinghai Lu.
-
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Merge tag 'pm+acpi-for-3.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI and power management fixes from Rafael Wysocki:
- cpuidle regression fix related to the initialization of state
kobjects from Krzysztof Mazur.
- cpuidle fix removing some not very useful code and making some
user-visible problems go away at the same time. From Daniel Lezcano.
- ACPI build fix from Yinghai Lu.
* tag 'pm+acpi-for-3.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpuidle: remove the power_specified field in the driver
ACPI / glue: Fix build with ACPI_GLUE_DEBUG set
cpuidle: fix number of initialized/destroyed states
Dave Jones hit this assert when doing a compile on recent git, with
CONFIG_XFS_DEBUG enabled:
XFS: Assertion failed: (char *)dup - (char *)hdr == be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)), file: fs/xfs/xfs_dir2_data.c, line: 828
Upon further digging, the tag found by xfs_dir2_data_unused_tag_p(dup)
contained "2" and not the proper offset, and I found that this value was
changed after the memmoves under "Use a stale leaf for our new entry."
in xfs_dir2_block_addname(), i.e.
memmove(&blp[mid + 1], &blp[mid],
(highstale - mid) * sizeof(*blp));
overwrote it.
What has happened is that the previous call to xfs_dir2_block_compact()
has rearranged things; it changes btp->count as well as the
blp array. So after we make that call, we must recalculate the
proper pointer to the leaf entries by making another call to
xfs_dir2_block_leaf_p().
Dave provided a metadump image which led to a simple reproducer
(create a particular filename in the affected directory) and this
resolves the testcase as well as the bug on his live system.
Thanks also to dchinner for looking at this one with me.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Tested-by: Dave Jones <davej@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
The int casts here make it easy to trigger an assert with a large
soft limit. For example, set a >4TB soft limit on an empty volume
to reproduce a (0 > -x) comparison due to an overflow of
d_blk_softlimit.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Per Dave Chinner suggestion, this patch:
1) Corrects the detection of whether a multi-segment buffer is
still tracking data.
2) Clears all the buffer log formats for a multi-segment buffer.
Signed-off-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Not every segment in a multi-segment buffer is dirty in a
transaction and they will not be outputted. The assert in
xfs_buf_item_format_segment() that checks for the at least
one chunk of data in the segment to be used is not necessary
true for multi-segmented buffers.
Signed-off-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Rename the bli_format structure to __bli_format to avoid
accidently confusing them with the bli_formats pointer.
Signed-off-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Commits starting at 77c1a08 introduced a multiple segment support
to xfs_buf. xfs_trans_buf_item_match() could not find a multi-segment
buffer in the transaction because it was looking at the single segment
block number rather than the multi-segment b_maps[0].bm.bn. This
results on a recursive buffer lock that can never be satisfied.
This patch:
1) Changed the remaining b_map accesses to be b_maps[0] accesses.
2) Renames the single segment b_map structure to __b_map to avoid
future confusion.
Signed-off-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
In commit 281dc5c5ec ("Give up on pushing CC_OPTIMIZE_FOR_SIZE") we
already changed the actual default value, but the help-text still
suggested 'y'. Fix the help text too, for all the same reasons.
Sadly, -Os keeps on generating some very suboptimal code for certain
cases, to the point where any I$ miss upside is swamped by the downside.
The main ones are:
- using "rep movsb" for memcpy, even on CPU's where that is
horrendously bad for performance.
- not honoring branch prediction information, so any I$ footprint you
win from smaller code, you lose from less code density in the I$.
- using divide instructions when that is very expensive.
Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix the build error:
drivers/built-in.o: In function `twl_probe':
drivers/mfd/twl-core.c:1256: undefined reference to `devm_regmap_init_i2c'
make: *** [vmlinux] Error 1
Signed-off-by: liu chuansheng <chuansheng.liu@intel.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
[ Samuel is busy, taking it directly - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[ We should make fun of people who can't speel too, but then we'd have
no time for any real work at all - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 1b963c81b1 ("lockdep, rwsem: provide down_write_nest_lock()")
contains a bug in a codepath when CONFIG_DEBUG_LOCK_ALLOC is disabled,
which causes down_read() to be called instead of down_write() by mistake
on such configurations. Fix that.
Reported-and-tested-by: Andrew Clayton <andrew@digital-domain.net>
Reported-and-tested-by: Zlatko Calusic <zlatko.calusic@iskon.hr>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Yet a few more fixes popped up in this week.
The biggest change here is the addition of pinctrl support for Atmel,
which turned out to be almost mandatory to make things working.
The rest are a few fixes for M-Audio usb-audio device and a fix for
regression of HD-audio HDMI codecs with alsactl in the recent kernel.
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Merge tag 'sound-3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
Pull second round of sound fixes from Takashi Iwai:
"Yet a few more fixes popped up in this week.
The biggest change here is the addition of pinctrl support for Atmel,
which turned out to be almost mandatory to make things working.
The rest are a few fixes for M-Audio usb-audio device and a fix for
regression of HD-audio HDMI codecs with alsactl in the recent kernel."
* tag 'sound-3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
ALSA: hda/hdmi - Work around "alsactl restore" errors
ALSA: usb-audio: selector map for M-Audio FT C400
ALSA: usb-audio: M-Audio FT C400 skip packet quirk
ALSA: usb-audio: correct M-Audio C400 clock source quirk
ALSA: usb - fix race in creation of M-Audio Fast track pro driver
ASoC: atmel-ssc: add pinctrl selection to driver
ARM: at91/dts: add pinctrl support for SSC peripheral
