linux/drivers/gpu/drm
Chris Wilson 90c1efdd12 drm: Return EBUSY if the framebuffer is unbound when flipping.
It looks like there is a race condition between unbinding a framebuffer
on a hotplug event and user space trying to flip:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000058
IP: [<ffffffffa008c7d3>] intel_crtc_page_flip+0xc9/0x39c [i915]
PGD 114724067 PUD 1145bd067 PMD 0
Oops: 0000 [#1] SMP
Pid: 10954, comm: X Not tainted 2.6.35-rc5_stable_20100714+ #1
P5Q-EM/P5Q-EM
RIP: 0010:[<ffffffffa008c7d3>]  [<ffffffffa008c7d3>]
intel_crtc_page_flip+0xc9/0x39c [i915]
RSP: 0018:ffff880114927cc8  EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88012df48320 RCX: ffff88010c945600
RDX: ffff880001a109c8 RSI: ffff88010c945840 RDI: ffff88012df48320
RBP: ffff880114927d18 R08: ffff88012df48280 R09: ffff88012df48320
R10: 0000000003c2e0b0 R11: 0000000000003246 R12: ffff88010c945840
R13: ffff88012df48000 R14: 0000000000000060 R15: ffff88012dbb8000
FS:  00007f9e6078e830(0000) GS:ffff880001a00000(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000058 CR3: 00000001177a8000 CR4: 00000000000406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process X (pid: 10954, threadinfo ffff880114926000, task
ffff88012a4a1690)
Stack:
 ffff88010c945600 ffff880115b176c0 ffff88012db10000 0000000000000246
<0> fffffff40006101c ffff88010c945600 00000000ffffffea ffff88010c945600
<0> ffff88012df48320 ffff88011b4b6780 ffff880114927d78 ffffffffa003bd0e
Call Trace:
 [<ffffffffa003bd0e>] drm_mode_page_flip_ioctl+0x1bc/0x214 [drm]
 [<ffffffffa00311fc>] drm_ioctl+0x25e/0x35e [drm]
 [<ffffffffa003bb52>] ? drm_mode_page_flip_ioctl+0x0/0x214 [drm]
 [<ffffffff810f1c3c>] vfs_ioctl+0x2a/0x9e
 [<ffffffff810f227e>] do_vfs_ioctl+0x531/0x565
 [<ffffffff810f2307>] sys_ioctl+0x55/0x77
 [<ffffffff810e56d6>] ? sys_read+0x47/0x6f
 [<ffffffff81002a2b>] system_call_fastpath+0x16/0x1b
Code: 45 d4 f4 ff ff ff 0f 84 e0 02 00 00 48 8b 4d b0 49 8d 9d 20 03 00 00 48
89 df 49 89 4c 24 38 49 8b 07 49 89 44 24 20 49 8b 47 20 <48> 8b 40 58 49 c7 04
24 00 00 00 00 49 c7 44 24 18 a9 a5 08 a0
RIP  [<ffffffffa008c7d3>] intel_crtc_page_flip+0xc9/0x39c [i915]
 RSP <ffff880114927cc8>
CR2: 0000000000000058

References:

  Bug 28811 - [page-flipping] GPU hang when modeset after unplugging
              another monitor (under compiz)
  https://bugs.freedesktop.org/show_bug.cgi?id=28811

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-07-21 11:26:07 +10:00
..
i2c
i810 include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
i830 include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
i915 Merge branch 'drm-tracepoints' into drm-testing 2010-07-07 18:38:44 +10:00
mga drm: Remove drm_resource wrappers 2010-06-01 10:07:24 +10:00
nouveau drm: add PCI requirements to low-level drivers. 2010-07-09 07:43:27 +10:00
r128 include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
radeon Merge branch 'drm-platform' into drm-testing 2010-07-07 18:37:35 +10:00
savage drm: Remove drm_resource wrappers 2010-06-01 10:07:24 +10:00
sis
tdfx
ttm Merge branch 'drm-intel-lru' into drm-testing 2010-07-07 18:37:37 +10:00
via Merge branch 'drm-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6 2010-05-04 19:08:12 -07:00
vmwgfx Merge branch 'drm-platform' into drm-testing 2010-07-07 18:37:35 +10:00
ati_pcigart.c ati_pcigart: fix printk format warning 2010-02-05 11:46:48 +10:00
drm_agpsupport.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
drm_auth.c drivers/gpu/drm: Use kzalloc 2010-05-18 15:57:05 +10:00
drm_buffer.c drm: Add generic multipart buffer. 2010-02-23 09:46:20 +10:00
drm_bufs.c Merge branch 'drm-platform' into drm-testing 2010-07-07 18:37:35 +10:00
drm_cache.c
drm_context.c
drm_crtc.c drm: Return EBUSY if the framebuffer is unbound when flipping. 2010-07-21 11:26:07 +10:00
drm_crtc_helper.c drm: unify crtc,connector,encoder,fb debug printing 2010-07-16 11:25:02 +10:00
drm_debugfs.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
drm_dma.c drivers/gpu/drm: Use kzalloc 2010-05-18 15:57:05 +10:00
drm_dp_i2c_helper.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
drm_drawable.c
drm_drv.c drm: Add support for platform devices to register as DRM devices 2010-06-01 10:07:39 +10:00
drm_edid.c drm: Add support for platform devices to register as DRM devices 2010-06-01 10:07:39 +10:00
drm_encoder_slave.c
drm_fb_helper.c drm: correctly update connector DPMS status in drm_fb_helper 2010-07-07 14:21:39 +10:00
drm_fops.c drivers/gpu/drm: Use kzalloc 2010-05-18 15:57:05 +10:00
drm_gem.c drm: Make sure the DRM offset matches the CPU 2010-06-01 10:07:57 +10:00
drm_hashtab.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
drm_info.c drm: Add support for platform devices to register as DRM devices 2010-06-01 10:07:39 +10:00
drm_ioc32.c
drm_ioctl.c drm: Add support for platform devices to register as DRM devices 2010-06-01 10:07:39 +10:00
drm_irq.c Merge branch 'drm-tracepoints' into drm-testing 2010-07-07 18:38:44 +10:00
drm_lock.c
drm_memory.c drivers/gpu/drm/drm_memory.c: fix check for end of loop 2010-04-28 18:41:51 +10:00
drm_mm.c drm: implement helper functions for scanning lru list 2010-07-07 12:29:51 +10:00
drm_modes.c drm/edid: Fix sync polarity for secondary GTF curve 2010-04-09 10:05:40 +10:00
drm_pci.c drm: Add support for platform devices to register as DRM devices 2010-06-01 10:07:39 +10:00
drm_platform.c drm: Add support for platform devices to register as DRM devices 2010-06-01 10:07:39 +10:00
drm_proc.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
drm_scatter.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
drm_sman.c
drm_stub.c drm: Add support for platform devices to register as DRM devices 2010-06-01 10:07:39 +10:00
drm_sysfs.c Merge branch 'drm-platform' into drm-testing 2010-07-07 18:37:35 +10:00
drm_trace.h drm: add per-event vblank event trace points 2010-07-02 14:03:24 +10:00
drm_trace_points.c drm: add vblank event trace point 2010-07-02 14:02:44 +10:00
drm_vm.c drm: Add __arm defines to DRM 2010-06-01 10:07:56 +10:00
Kconfig drm: add PCI requirements to low-level drivers. 2010-07-09 07:43:27 +10:00
Makefile Merge branch 'drm-tracepoints' into drm-testing 2010-07-07 18:38:44 +10:00
README.drm

************************************************************
* For the very latest on DRI development, please see:      *
*     http://dri.freedesktop.org/                          *
************************************************************

The Direct Rendering Manager (drm) is a device-independent kernel-level
device driver that provides support for the XFree86 Direct Rendering
Infrastructure (DRI).

The DRM supports the Direct Rendering Infrastructure (DRI) in four major
ways:

    1. The DRM provides synchronized access to the graphics hardware via
       the use of an optimized two-tiered lock.

    2. The DRM enforces the DRI security policy for access to the graphics
       hardware by only allowing authenticated X11 clients access to
       restricted regions of memory.

    3. The DRM provides a generic DMA engine, complete with multiple
       queues and the ability to detect the need for an OpenGL context
       switch.

    4. The DRM is extensible via the use of small device-specific modules
       that rely extensively on the API exported by the DRM module.


Documentation on the DRI is available from:
    http://dri.freedesktop.org/wiki/Documentation
    http://sourceforge.net/project/showfiles.php?group_id=387
    http://dri.sourceforge.net/doc/

For specific information about kernel-level support, see:

    The Direct Rendering Manager, Kernel Support for the Direct Rendering
    Infrastructure
    http://dri.sourceforge.net/doc/drm_low_level.html

    Hardware Locking for the Direct Rendering Infrastructure
    http://dri.sourceforge.net/doc/hardware_locking_low_level.html

    A Security Analysis of the Direct Rendering Infrastructure
    http://dri.sourceforge.net/doc/security_low_level.html