WARNING: CPU: 0 PID: 3634 at drivers/gpu/drm/drm_irq.c:1141 drm_wait_one_vblank

[Michal Hocko]

On Wed 01-07-15 10:26:39, Daniel Vetter wrote:
> On Tue, Jun 30, 2015 at 10:13:35PM +0200, Michal Hocko wrote:
> > On Tue 30-06-15 18:59:29, Daniel Vetter wrote:
[...]
> > > Also it might be time to start bisecting this if you can readily reproduce it.
> > 
> > Yes, I can reproduce it just by switching to the text console. Sometimes
> > it is the first attempt already but sometimes it takes several attempts.
> > I will try to go back to 4.0 and bisect it then.
> 
> Yes please do, since this is a confusing regression I think the bisect
> result will be the fastest way forward.

OK, managed to bisect to cf4c7c12258e ("drm/i915: Make all plane
disables use 'update_plane' (v5)") (CC people involved - the thread
starts here: http://marc.info/?l=dri-devel&m=143566543432613&w=2 for
your reference).

I do not see the warning when I revert the commit directly on top of
cf4c7c12258e but I cannot cleanly revert it on top of the current Linus'
tree. Anything more I can give you to help to further debug the issue?

Bisect log is:
git bisect start
# bad: [c517d838eb7d07bbe9507871fab3931deccff539] Linux 4.0-rc1
git bisect bad c517d838eb7d07bbe9507871fab3931deccff539
# good: [bfa76d49576599a4b9f9b7a71f23d73d6dcff735] Linux 3.19
git bisect good bfa76d49576599a4b9f9b7a71f23d73d6dcff735
# good: [02f1f2170d2831b3233e91091c60a66622f29e82] kernel.h: remove ancient __FUNCTION__ hack
git bisect good 02f1f2170d2831b3233e91091c60a66622f29e82
# bad: [796e1c55717e9a6ff5c81b12289ffa1ffd919b6f] Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux
git bisect bad 796e1c55717e9a6ff5c81b12289ffa1ffd919b6f
# good: [9682ec9692e5ac11c6caebd079324e727b19e7ce] Merge tag 'driver-core-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
git bisect good 9682ec9692e5ac11c6caebd079324e727b19e7ce
# good: [a9724125ad014decf008d782e60447c811391326] Merge tag 'tty-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
git bisect good a9724125ad014decf008d782e60447c811391326
# bad: [f43dff0ee00a259f524ce17ba4f8030553c66590] Merge tag 'drm-amdkfd-next-fixes-2015-01-25' of git://people.freedesktop.org/~gabbayo/linux into drm-next
git bisect bad f43dff0ee00a259f524ce17ba4f8030553c66590
# good: [b942c653ae265abbd31032f3b4f5f857e5c7c723] Merge tag 'trace-sh-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
git bisect good b942c653ae265abbd31032f3b4f5f857e5c7c723
# good: [fcf3aac5fc307f0cae429f5844ddc25761662858] drm/i915: remove unused power_well/get_cdclk_freq api
git bisect good fcf3aac5fc307f0cae429f5844ddc25761662858
# bad: [4f4d89af78682f2ed1cf6745794804817f867bba] Merge tag 'drm-amdkfd-next-2015-01-09' of git://people.freedesktop.org/~gabbayo/linux into drm-next
git bisect bad 4f4d89af78682f2ed1cf6745794804817f867bba
# bad: [64387b613a43713d0e03d9d43bfbb1727e8475e1] drm/i915: Protect against leaks in pipe_crc_set_source
git bisect bad 64387b613a43713d0e03d9d43bfbb1727e8475e1
# good: [bfc882b4e30fbc169ecfe3508378623743806f56] drm/i915: Flatten engine init control flow
git bisect good bfc882b4e30fbc169ecfe3508378623743806f56
# good: [2b875c22fa77dfc895d3cf8287a553813d3e64c8] drm/i915: Make intel_plane_state subclass drm_plane_state
git bisect good 2b875c22fa77dfc895d3cf8287a553813d3e64c8
# bad: [15a17aae5f803551981a7acc6a4058b247a7452c] drm/i915: Check mask/bit helper functions
git bisect bad 15a17aae5f803551981a7acc6a4058b247a7452c
# bad: [146d84f0f2707bfe2c67114eeefac30da8584b3b] drm/i915: Fix up seqno -> request merge issues
git bisect bad 146d84f0f2707bfe2c67114eeefac30da8584b3b
# good: [c59cb179aaf444931cf9c547a514e383da3d2526] drm/i915: Consolidate top-level .update_plane() handlers
git bisect good c59cb179aaf444931cf9c547a514e383da3d2526
# bad: [cf4c7c12258ed9367f4fc45238f5f50d2db892c1] drm/i915: Make all plane disables use 'update_plane' (v5)
git bisect bad cf4c7c12258ed9367f4fc45238f5f50d2db892c1
# good: [e614c3c946ae5b50a679d65d2c981615d8ceccab] drm/i915: Ensure state->crtc is non-NULL for plane updates
git bisect good e614c3c946ae5b50a679d65d2c981615d8ceccab
# first bad commit: [cf4c7c12258ed9367f4fc45238f5f50d2db892c1] drm/i915: Make all plane disables use 'update_plane' (v5)
-- 
Michal Hocko
SUSE Labs