linux/include/drm
Chris Wilson 752d2635eb drm: Take lock around probes for drm_fb_helper_hotplug_event
We need to hold the dev->mode_config.mutex whilst detecting the output
status. But we also need to drop it for the call into
drm_fb_helper_single_fb_probe(), which indirectly acquires the lock when
attaching the fbcon.

Failure to do so exposes a race with normal output probing. Detected by
adding some warnings that the mutex is held to the backend detect routines:

[   17.772456] WARNING: at drivers/gpu/drm/i915/intel_crt.c:471 intel_crt_detect+0x3e/0x373 [i915]()
[   17.772458] Hardware name: Latitude E6400
[   17.772460] Modules linked in: ....
[   17.772582] Pid: 11, comm: kworker/0:1 Tainted: G        W 2.6.38.4-custom.2 #8
[   17.772584] Call Trace:
[   17.772591]  [<ffffffff81046af5>] ? warn_slowpath_common+0x78/0x8c
[   17.772603]  [<ffffffffa03f3e5c>] ? intel_crt_detect+0x3e/0x373 [i915]
[   17.772612]  [<ffffffffa0355d49>] ?  drm_helper_probe_single_connector_modes+0xbf/0x2af [drm_kms_helper]
[   17.772619]  [<ffffffffa03534d5>] ?  drm_fb_helper_probe_connector_modes+0x39/0x4d [drm_kms_helper]
[   17.772625]  [<ffffffffa0354760>] ?  drm_fb_helper_hotplug_event+0xa5/0xc3 [drm_kms_helper]
[   17.772633]  [<ffffffffa035577f>] ? output_poll_execute+0x146/0x17c [drm_kms_helper]
[   17.772638]  [<ffffffff81193c01>] ? cfq_init_queue+0x247/0x345
[   17.772644]  [<ffffffffa0355639>] ? output_poll_execute+0x0/0x17c [drm_kms_helper]
[   17.772648]  [<ffffffff8105b540>] ? process_one_work+0x193/0x28e
[   17.772652]  [<ffffffff8105c6bc>] ? worker_thread+0xef/0x172
[   17.772655]  [<ffffffff8105c5cd>] ? worker_thread+0x0/0x172
[   17.772658]  [<ffffffff8105c5cd>] ? worker_thread+0x0/0x172
[   17.772663]  [<ffffffff8105f767>] ? kthread+0x7a/0x82
[   17.772668]  [<ffffffff8100a724>] ? kernel_thread_helper+0x4/0x10
[   17.772671]  [<ffffffff8105f6ed>] ? kthread+0x0/0x82
[   17.772674]  [<ffffffff8100a720>] ? kernel_thread_helper+0x0/0x10

Reported-by:  Frederik Himpe <fhimpe@telenet.be>
References: https://bugs.freedesktop.org/show_bug.cgi?id=36394
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2011-05-16 12:01:43 +10:00
..
i2c drm: Import driver for the sil164 I2C TMDS transmitter. 2010-08-02 10:21:13 +10:00
ttm Merge branch 'for-linus2' of git://git.profusion.mobi/users/lucas/linux-2.6 2011-04-07 11:14:49 -07:00
drm_buffer.h drm: Add generic multipart buffer. 2010-02-23 09:46:20 +10:00
drm_cache.h drm/ttm: consolidate cache flushing code in one place. 2009-08-27 09:53:47 +10:00
drm_core.h drm: Fix support for PCI domains 2010-08-10 08:20:20 +10:00
drm_crtc_helper.h drm, kdb, kms: Change mode_set_base_atomic() enter argument to be an enum 2010-10-19 14:13:33 +10:00
drm_crtc.h Merge branch 'for-linus2' of git://git.profusion.mobi/users/lucas/linux-2.6 2011-04-07 11:14:49 -07:00
drm_dp_helper.h drm/i915: fetch eDP configuration data from the VBT 2010-10-08 10:28:21 +01:00
drm_edid.h drm/edid: Add detailed block walk for CEA extensions 2010-08-10 10:46:57 +10:00
drm_encoder_slave.h drm/kms: no need to return void value (encoder) 2009-08-19 16:06:49 +10:00
drm_fb_helper.h drm: Take lock around probes for drm_fb_helper_hotplug_event 2011-05-16 12:01:43 +10:00
drm_fixed.h drm: move radeon_fixed.h to shared drm_fixed.h header 2010-05-18 18:21:33 +10:00
drm_global.h drm: move ttm global code to core drm 2010-08-04 09:46:06 +10:00
drm_hashtab.h drm: Remove unused members from struct drm_open_hash 2011-02-23 11:16:40 +10:00
drm_mem_util.h drm/ttm: use drm calloc large and free large 2010-03-15 10:31:43 +10:00
drm_memory.h includecheck fix: include/drm, drm_memory.h 2009-09-20 16:02:58 +05:30
drm_mm.h drm: mm: fix debug output 2011-05-09 09:14:45 +10:00
drm_mode.h Fix common misspellings 2011-03-31 11:26:23 -03:00
drm_os_linux.h drm/i915: add i915_lp_ring_sync helper 2009-11-05 14:47:07 -08:00
drm_pciids.h drm/radeon/kms: add some new pci ids 2011-05-04 09:28:59 +10:00
drm_sarea.h drm: move to kref per-master structures. 2008-12-29 17:47:22 +10:00
drm_sman.h drm: reorganise drm tree to be more future proof. 2008-07-14 10:45:01 +10:00
drm_sysfs.h drm: Enable drm drivers to add drm sysfs devices. 2009-08-19 16:08:51 +10:00
drm_usb.h drm: add usb framework 2011-02-07 13:09:42 +10:00
drm.h drm/vblank: update recently added vbl interface to be more future proof. 2011-03-24 21:28:46 +10:00
drmP.h Fix common misspellings 2011-03-31 11:26:23 -03:00
i810_drm.h drm: reorganise drm tree to be more future proof. 2008-07-14 10:45:01 +10:00
i915_drm.h drm/i915: Allow relocation deltas outside of target bo 2011-03-01 16:01:02 +00:00
intel-gtt.h intel-gtt: export api for drm/i915 2010-11-23 20:14:47 +00:00
Kbuild drm: remove i830 driver 2011-02-07 12:14:18 +10:00
mga_drm.h Fix common misspellings 2011-03-31 11:26:23 -03:00
nouveau_drm.h drm/nv50: support for compression 2011-02-25 06:46:07 +10:00
r128_drm.h drm: reorganise drm tree to be more future proof. 2008-07-14 10:45:01 +10:00
radeon_drm.h drm/radeon/kms: fix gart setup on fusion parts (v2) 2011-05-04 10:16:40 +10:00
savage_drm.h Fix common misspellings 2011-03-31 11:26:23 -03:00
sis_drm.h drm: reorganise drm tree to be more future proof. 2008-07-14 10:45:01 +10:00
via_drm.h drm: Add compatibility #ifdefs for *BSD 2009-12-04 08:59:28 +10:00
vmwgfx_drm.h Fix common misspellings 2011-03-31 11:26:23 -03:00