[PULL] kms locking rework
Daniel Vetter
daniel at ffwll.ch
Sun Jan 20 07:32:09 PST 2013
Hi Dave,
I've figured a pull request is easier ;-)
Changes since the patchbomb on dri-devel:
- Added a patch to adjust the new omapdrm code in 3.8-rc4, reviewed by Rob
Clark on irc (hence also why the baseline of this pull is 3.8-rc4).
- Slightly fixed/clarified some commit messages and fixed one spelling
fail in a comment.
- Sprinkled Rob's r-b tags over the patches (for drm core changes +
omapdrm).
Imo the individual patches contain really detailed commit messages, so for
the merge commit just a quick overview:
The aim of this locking rework is that ioctls which a compositor should be
might call for every frame (set_cursor, page_flip, addfb, rmfb and
getfb/create_handle) should not be able to block on kms background
activities like output detection. And since each EDID read takes about
25ms (in the best case), that always means we'll drop at least one frame.
The solution is to add per-crtc locking for these ioctls, and restrict
background activities to only use the global lock. Change-the-world type
of events (modeset, dpms, ...) need to grab all locks.
Two tricky parts arose in the conversion:
- A lot of current code assumes that a kms fb object can't disappear while
holding the global lock, since the current code serializes fb
destruction with it. Hence proper lifetime management using the already
created refcounting for fbs need to be instantiated for all ioctls and
interfaces/users.
- The rmfb ioctl removes the to-be-deleted fb from all active users. But
unconditionally taking the global kms lock to do so introduces an
unacceptable potential stall point. And obviously changing the userspace
abi isn't on the table, either. Hence this conversion opportunistically
checks whether the rmfb ioctl holds the very last reference, which
guarantees that the fb isn't in active use on any crtc or plane (thanks
to the conversion to the new lifetime rules using proper refcounting).
Only if this is not the case will the code go through the slowpath and
grab all modeset locks. Sane compositors will never hit this path and so
avoid the stall, but userspace relying on these semantics will also not
break.
All these cases are exercised by the newly added subtests for the i-g-t
kms_flip, tested on a machine where a full detect cycle takes around 100
ms. It works, and no frames are dropped any more with these patches
applied. kms_flip also contains a special case to exercise the
above-describe rmfb slowpath.
Yours, Daniel
The following changes since commit 7d1f9aeff1ee4a20b1aeb377dd0f579fe9647619:
Linux 3.8-rc4 (2013-01-17 19:25:45 -0800)
are available in the git repository at:
git://people.freedesktop.org/~danvet/drm-intel drm-kms-locking
for you to fetch changes up to 57c45428f2b005e95bbc6706cd61574183ed8522:
drm/fb_helper: check whether fbcon is bound (2013-01-20 15:59:55 +0100)
----------------------------------------------------------------
Daniel Vetter (36):
drm: review locking rules in drm_crtc.c
drm/doc: integrate drm_crtc.c kerneldoc
drm/<drivers>: reorder framebuffer init sequence
drm/vmwgfx: reorder framebuffer init sequence
drm/gma500: move fbcon restore to lastclose
drm/nouveau: protect evo_wait/evo_kick sections with a channel mutex
drm/nouveau: try to protect nbo->pin_refcount
drm/<drivers>: Unified handling of unimplemented fb->create_handle
drm: encapsulate crtc->set_config calls
drm: add drm_modeset_lock|unlock_all
drm/i915: use drm_modeset_lock_all
drm/gma500: use drm_modeset_lock_all
drm/ast: use drm_modeset_lock_all
drm/shmobile: use drm_modeset_lock_all
drm/vmwgfx: use drm_modeset_lock_all
omapdrm: use modeset_lock_all
drm: add per-crtc locks
drm: only take the crtc lock for ->cursor_set
drm: only take the crtc lock for ->cursor_move
drm: revamp locking around fb creation/destruction
drm: create drm_framebuffer_lookup
drm: revamp framebuffer cleanup interfaces
drm: reference framebuffers which are on the idr
drm: nest modeset locks within fpriv->fbs_lock
drm: push modeset_lock_all into ->fb_create driver callbacks
drm: don't take modeset locks in getfb ioctl
drm: fb refcounting for dirtyfb_ioctl
drm: refcounting for sprite framebuffers
drm: refcounting for crtc framebuffers
drm/i915: dump refcount into framebuffer debugfs file
drm/vmwgfx: add proper framebuffer refcounting
drm: optimize drm_framebuffer_remove
drm: only grab the crtc lock for pageflips
drm: don't hold crtc mutexes for connector ->detect callbacks
drm/doc: updates for new framebuffer lifetime rules
drm/fb_helper: check whether fbcon is bound
Documentation/DocBook/drm.tmpl | 63 ++-
drivers/gpu/drm/ast/ast_drv.c | 4 +-
drivers/gpu/drm/ast/ast_drv.h | 2 +
drivers/gpu/drm/ast/ast_fb.c | 1 +
drivers/gpu/drm/ast/ast_main.c | 12 +-
drivers/gpu/drm/cirrus/cirrus_fbdev.c | 1 +
drivers/gpu/drm/cirrus/cirrus_main.c | 12 +-
drivers/gpu/drm/drm_crtc.c | 792 +++++++++++++++++------------
drivers/gpu/drm/drm_fb_cma_helper.c | 15 +-
drivers/gpu/drm/drm_fb_helper.c | 65 ++-
drivers/gpu/drm/drm_fops.c | 1 +
drivers/gpu/drm/exynos/exynos_drm_fbdev.c | 4 +-
drivers/gpu/drm/gma500/framebuffer.c | 29 +-
drivers/gpu/drm/gma500/psb_device.c | 8 +-
drivers/gpu/drm/gma500/psb_drv.c | 14 +-
drivers/gpu/drm/i2c/ch7006_drv.c | 2 +-
drivers/gpu/drm/i915/i915_debugfs.c | 15 +-
drivers/gpu/drm/i915/intel_display.c | 21 +-
drivers/gpu/drm/i915/intel_dp.c | 2 +
drivers/gpu/drm/i915/intel_fb.c | 5 +-
drivers/gpu/drm/i915/intel_lvds.c | 4 +-
drivers/gpu/drm/i915/intel_overlay.c | 14 +-
drivers/gpu/drm/i915/intel_sprite.c | 8 +-
drivers/gpu/drm/mgag200/mgag200_fb.c | 1 +
drivers/gpu/drm/mgag200/mgag200_main.c | 16 +-
drivers/gpu/drm/nouveau/nouveau_bo.c | 22 +-
drivers/gpu/drm/nouveau/nouveau_bo.h | 2 +
drivers/gpu/drm/nouveau/nouveau_display.c | 10 +-
drivers/gpu/drm/nouveau/nouveau_fbcon.c | 1 +
drivers/gpu/drm/nouveau/nv04_display.c | 2 +-
drivers/gpu/drm/nouveau/nv17_tv.c | 2 +-
drivers/gpu/drm/nouveau/nv50_display.c | 10 +
drivers/gpu/drm/radeon/radeon_cursor.c | 8 +-
drivers/gpu/drm/radeon/radeon_display.c | 2 +-
drivers/gpu/drm/radeon/radeon_fb.c | 2 +
drivers/gpu/drm/shmobile/shmob_drm_drv.c | 4 +-
drivers/gpu/drm/udl/udl_fb.c | 4 +-
drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 2 +-
drivers/gpu/drm/vmwgfx/vmwgfx_ioctl.c | 38 +-
drivers/gpu/drm/vmwgfx/vmwgfx_kms.c | 87 ++--
drivers/staging/omapdrm/omap_crtc.c | 8 +-
drivers/staging/omapdrm/omap_debugfs.c | 2 +
drivers/staging/omapdrm/omap_drv.c | 4 +-
drivers/staging/omapdrm/omap_fb.c | 16 +-
drivers/staging/omapdrm/omap_fbdev.c | 8 +-
include/drm/drmP.h | 13 +
include/drm/drm_crtc.h | 30 ++
47 files changed, 836 insertions(+), 552 deletions(-)
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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