i915 kernel warning

[Mihai Donțu]

On Wed, 6 Aug 2014 22:29:54 +0200 Daniel Vetter wrote:
> On Wed, Aug 06, 2014 at 10:03:46PM +0300, Mihai Donțu wrote:
> > Hi,
> > 
> > This just happened to me:
> > 
> > Aug  6 21:37:37 mdontu-l kernel: ------------[ cut here ]------------
> > Aug  6 21:37:37 mdontu-l kernel: WARNING: CPU: 3 PID: 4823 at drivers/gpu/drm/i915/intel_display.c:3313 intel_crtc_wait_for_pending_flips+0x16c/0x180()
> > Aug  6 21:37:37 mdontu-l kernel: Modules linked in: hdaps(O) tp_smapi(O) thinkpad_ec(O) vboxnetadp(O) vboxnetflt(O) vboxdrv(O) iwldvm iwlwifi e1000e
> > Aug  6 21:37:37 mdontu-l kernel: CPU: 3 PID: 4823 Comm: X Tainted: G           O  3.16.0-gentoo #2
> > Aug  6 21:37:37 mdontu-l kernel: Hardware name: LENOVO 4178A4G/4178A4G, BIOS 83ET76WW (1.46 ) 07/05/2013
> > Aug  6 21:37:37 mdontu-l kernel:  0000000000000009 ffff88041d63fbf8 ffffffff93c212a4 0000000000000000
> > Aug  6 21:37:37 mdontu-l kernel:  ffff88041d63fc30 ffffffff930e3a2d 0000000000000000 ffff880427b7c000
> > Aug  6 21:37:37 mdontu-l kernel:  ffff880426f380a8 ffff880426ddf800 ffff880426ddf800 ffff88041d63fc40
> > Aug  6 21:37:37 mdontu-l kernel: Call Trace:
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff93c212a4>] dump_stack+0x45/0x56
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff930e3a2d>] warn_slowpath_common+0x7d/0xa0
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff930e3b0a>] warn_slowpath_null+0x1a/0x20
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff936994dc>] intel_crtc_wait_for_pending_flips+0x16c/0x180
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff931240f0>] ? __wake_up_sync+0x20/0x20
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff9369c753>] intel_crtc_disable_planes+0x33/0x1c0
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff9369cd20>] ironlake_crtc_disable+0x50/0x970
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff936457bf>] ? drm_modeset_lock+0x2f/0xd0
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff93c27fe2>] ? mutex_lock+0x12/0x30
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff9369e0af>] intel_crtc_update_dpms+0x6f/0xa0
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff936a1f09>] intel_connector_dpms+0x59/0x70
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff9363c8c9>] drm_mode_obj_set_property_ioctl+0x399/0x3a0
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff9363c900>] drm_mode_connector_property_set_ioctl+0x30/0x40
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff9362b83f>] drm_ioctl+0x1df/0x680
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff935cf8dc>] ? backlight_generate_event+0x5c/0x80
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff935d0021>] ? brightness_store+0x91/0xd0
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff93244a0c>] ? fsnotify+0x27c/0x350
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff9321b498>] do_vfs_ioctl+0x2c8/0x490
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff9320b911>] ? __sb_end_write+0x31/0x60
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff93209512>] ? vfs_write+0x1c2/0x200
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff9321b6a1>] SyS_ioctl+0x41/0x80
> > Aug  6 21:37:37 mdontu-l kernel:  [<ffffffff93c29b52>] system_call_fastpath+0x16/0x1b
> > Aug  6 21:37:37 mdontu-l kernel: ---[ end trace 131b19886670715a ]---
> 
> If you can reproduce this somehow, please boot with drm.debug=0xe and
> attach the complete dmesg up to the WARNING. We seem to loose track of
> pageflips under obscure circumstances sometimes. We have more band-aids
> queued up, but fixing the underlying issue would be better ofc.

I don't know how to reproduce it, but I've added the option to my
kernel command line. It does not seem to introduce any noticeable
performance degradation so I'll keep it on until the issue reappears.

Thanks,

> > X appeared to have stopped rendering (or nothing goes through), but the
> > applications worked fine (I still had sound from a video). My video
> > card is:
> > 
> > 00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09) (prog-if 00 [VGA controller])
> >         Subsystem: Lenovo Device 21d0
> >         Flags: bus master, fast devsel, latency 0, IRQ 43
> >         Memory at f1400000 (64-bit, non-prefetchable) [size=4M]
> >         Memory at e0000000 (64-bit, prefetchable) [size=256M]
> >         I/O ports at 6000 [size=64]
> >         Expansion ROM at <unassigned> [disabled]
> >         Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit-
> >         Capabilities: [d0] Power Management version 2
> >         Capabilities: [a4] PCI Advanced Features
> >         Kernel driver in use: i915
> > 
> > I was able to switch to the terminal and reboot.
> > 
> > I suspect this is new in 3.16 and I've noticed some other oddities
> > since I upgraded from 3.15.8:
> >  * when adjusting the screen brightness, the minimum setting is now
> >    "LCD off";
> >  * when watching a video in fullscreen, I can see a flicker every 10s
> >    or so.

-- 
Mihai Donțu