On 2020-11-08 14:06:00 +0000 Jonathan Gray <j...@jsg.id.au> wrote:
On Sun, Nov 08, 2020 at 01:09:40PM +0000, Anthony Richardby wrote:
On 2020-11-08 11:14:50 +0000 Jonathan Gray <j...@jsg.id.au> wrote:
On Sun, Nov 08, 2020 at 10:51:11AM +0000, Anthony Richardby wrote:
> On 2020-11-08 02:40:26 +0000 Jonathan Gray <j...@jsg.id.au> wrote:
> > > On Sat, Nov 07, 2020 at 04:01:34PM +0000, Anthony Richardby
wrote:
> > > Hey,
> > > I'm experiencing a kernel panic whenever I run glxgears, or it
> > would
> > > seem when I try to run other gpu-related tasks. I first
noticed
> > this
> > > when playing video via the application 'mpv', after a couple
of
> > > seconds of video the system freezes!! I've got the trace
output
> > for
> > > that as the time delay allows me to switch out of X11 to a
console
> > > before the system crashes. Anyway after this I tried
'glxgears'
> > and
> > > that crashes immediately (so I'm unable to get the trace, but
it
> > > sounds like it's related?).
> > > > Just wondering if anyone else is able to reproduce this on
their
> > > powerbooks / other g4 macs, does glxgears work for you?
> > > > Pic of the trace output: https://postimg.cc/wRLGLKdF
> > > What is the actual panic message?
> > > For the archives the trace was:
> > > panic(b6ae0c) at panic+0x154
> > mtx_enter(0) at mtx_enter+0x8c
> > drm_update_vblank_count(2a0fcdf8,e000a000,b6ae78) at
> > drm_update_vblank_count+0x4b8
> > drm_handle_vblank(2000611,82720e) at drm_handle_vblank+0xd8
> > r100_irq_process(a19ca0) at r100_irq_process+0x110
> > radeon_driver_irq_handler_kms(0) at
> > radeon_driver_irq_handler_kms+0x28
> > openpic_ext_intr() at openpic_ext_intr+0x274
> > extint_call() at extint_call
> > --- interrupt ---
> > at 0xe7055e1c
> > drm_wait_vblank_ioctl(e0732f00,e06b9b84,e7055c60) at
> > drm_wait_vblank_ioctl+0xb2
> > drm_do_ioctl(251571d0) at drm_do_ioctl+0x298
> > drmioctl(25157100,e7055ca8,990000,c010643a,3a033428) at
> > drmioctl+0xbc
> > > >
> The panic message is:
> panic: mtx 0xe024cc50: locking against myself
> > I forgot to mention that this is new in 6.8, I can run
glxgears/play
> video with mpv fine using 6.7.
> The seqlock is used from an interrupt context
drm_update_vblank_count() -> store_vblank()
> Can you try a kernel with the following diff?
Patch against 6.8 branch.
> Index: sys/dev/pci/drm/drm_vblank.c
===================================================================
RCS file: /cvs/src/sys/dev/pci/drm/drm_vblank.c,v
retrieving revision 1.6
diff -u -p -r1.6 drm_vblank.c
--- sys/dev/pci/drm/drm_vblank.c 29 Jul 2020 09:52:21 -0000 1.6
+++ sys/dev/pci/drm/drm_vblank.c 8 Nov 2020 11:04:58 -0000
@@ -481,7 +481,7 @@ int drm_vblank_init(struct drm_device *d
init_waitqueue_head(&vblank->queue);
setup_timer(&vblank->disable_timer, vblank_disable_fn,
(unsigned long)vblank);
- seqlock_init(&vblank->seqlock, IPL_NONE);
+ seqlock_init(&vblank->seqlock, IPL_TTY);
}
> DRM_INFO("Supports vblank timestamp caching Rev 2
(21.10.2013).\n");
>
Thanks for the time taken to look into this and offer this diff!
Unfortunately its still crashing, the trace and panic message look to
be the same:
https://postimg.cc/G4KNQ9c6
I've managed to use ports clang and lldb to build and inspect a
powerpc
drm_vblank.o and it points to
src/sys/dev/pci/drm/include/linux/atomic.h:165:2
which is the ilp32 version of atomic64_read().
The following patch makes sure the lock involved is initialised.
Index: sys/dev/pci/drm/drm_vblank.c
===================================================================
RCS file: /cvs/src/sys/dev/pci/drm/drm_vblank.c,v
retrieving revision 1.6
diff -u -p -r1.6 drm_vblank.c
--- sys/dev/pci/drm/drm_vblank.c 29 Jul 2020 09:52:21 -0000 1.6
+++ sys/dev/pci/drm/drm_vblank.c 8 Nov 2020 13:51:27 -0000
@@ -481,7 +481,8 @@ int drm_vblank_init(struct drm_device *d
init_waitqueue_head(&vblank->queue);
setup_timer(&vblank->disable_timer, vblank_disable_fn,
(unsigned long)vblank);
- seqlock_init(&vblank->seqlock, IPL_NONE);
+ seqlock_init(&vblank->seqlock, IPL_TTY);
+ atomic64_set(&vblank->count, 0);
}
DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
Absolute rockstar! That looks to have done the trick, I've been
watching a video in mpv while running glxgears for a good 10 minutes
and everything it's still up and running.
Many thanks for your help, I'm looking forward to updating my other
machine to 6.8 now that this is working.
