<html>
    <head>
      <base href="https://bugs.freedesktop.org/" />
    </head>
    <body>
      <p>
        <div>
            <b><a class="bz_bug_link 
          bz_status_NEEDINFO "
   title="NEEDINFO --- - [945GM bisected] screen blank on S3 resume on"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=72782#c21">Comment # 21</a>
              on <a class="bz_bug_link 
          bz_status_NEEDINFO "
   title="NEEDINFO --- - [945GM bisected] screen blank on S3 resume on"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=72782">bug 72782</a>
              from <span class="vcard"><a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> <span class="fn">Chris Wilson</span></a>
</span></b>
        <pre>(In reply to <a href="show_bug.cgi?id=72782#c20">comment #20</a>)
<span class="quote">> Today's mainline kernel (top commit 85ce70fdf48aa290b4845311c2dd815d7f8d1fa5)

> [  241.352344] INFO: task systemd-udevd:381 blocked for more than 120
> seconds.
> [  241.352420]       Tainted: PF          O 3.13.0-3-generic #18-Ubuntu
> [  241.352474] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables
> this message.
> [  241.352532] systemd-udevd   D f4fd7a24     0   381    270 0x00000004
> [  241.352552]  f4fd7a4c 00000086 c12f0573 f4fd7a24 c18294f8 c1a7c780
> 00000001 00000001
> [  241.352582]  c1a7c780 f5858000 f68a0d00 0003d1d6 00000000 f4fd7a1c
> f86e97df 1b762573
> [  241.352608]  f86e97e1 f86e97e1 f86ee998 f4fd7a60 c12f29dc 00000001
> 00000000 0000ff02
> [  241.352635] Call Trace:
> [  241.352663]  [<c12f0573>] ? format_decode+0x323/0x390
> [  241.352708]  [<c12f29dc>] ? vsnprintf+0x2cc/0x3d0
> [  241.352728]  [<c12f0001>] ? put_dec_trunc8+0x61/0xa0
> [  241.352750]  [<c16415a3>] schedule_preempt_disabled+0x23/0x60
> [  241.352766]  [<c1642eed>] __mutex_lock_slowpath+0x10d/0x171
> [  241.352782]  [<c164241c>] mutex_lock+0x1c/0x28
> [  241.352910]  [<f8d93aa2>] intel_get_load_detect_pipe+0x152/0x3a0 [i915]
> [  241.353059]  [<f8dc3142>] ? gen4_read32+0x32/0xb0 [i915]
> [  241.353075]  [<c12f2b6a>] ? snprintf+0x1a/0x20
> [  241.353195]  [<f8d9516d>] intel_modeset_setup_hw_state+0xa7d/0xae0 [i915]
> [  241.353273]  [<f86cffd8>] ? drm_mode_config_reset+0x98/0xb0 [drm]
> [  241.353392]  [<f8d951fe>] intel_modeset_gem_init+0x2e/0x40 [i915]
> [  241.353490]  [<f8d5abfb>] i915_driver_load+0xb3b/0xdc0 [i915]
> [  241.353586]  [<f8d57e10>] ? i915_switcheroo_set_state+0xa0/0xa0 [i915]
> [  241.353706]  [<f86cbcab>] drm_dev_register+0x8b/0x1a0 [drm]
> [  241.353768]  [<f86cd78e>] drm_get_pci_dev+0x7e/0x120 [drm]
> [  241.353797]  [<c11d8e37>] ? sysfs_do_create_link_sd.isra.2+0xa7/0x1c0
> [  241.353897]  [<f8d575ea>] i915_pci_probe+0x3a/0x80 [i915]
> [  241.353918]  [<c132870f>] pci_device_probe+0x6f/0xc0
> [  241.353934]  [<c11d8f75>] ? sysfs_create_link+0x25/0x40
> [  241.353956]  [<c13faf65>] driver_probe_device+0x105/0x380
> [  241.353972]  [<c1328662>] ? pci_match_device+0xb2/0xc0
> [  241.353992]  [<c13fb291>] __driver_attach+0x71/0x80
> [  241.354008]  [<c13fb220>] ? __device_attach+0x40/0x40
> [  241.354026]  [<c13f93c7>] bus_for_each_dev+0x47/0x80
> [  241.354043]  [<c13fa9ce>] driver_attach+0x1e/0x20
> [  241.354057]  [<c13fb220>] ? __device_attach+0x40/0x40
> [  241.354072]  [<c13fa627>] bus_add_driver+0x157/0x230
> [  241.354093]  [<c13fb859>] driver_register+0x59/0xe0
> [  241.354111]  [<c10487a0>] ? __set_pmd_pte+0xa0/0xa0
> [  241.354130]  [<c1327142>] __pci_register_driver+0x32/0x40
> [  241.354191]  [<f86cd925>] drm_pci_init+0xf5/0x100 [drm]
> [  241.354223]  [<f8655000>] ? 0xf8654fff
> [  241.354316]  [<f865505e>] i915_init+0x5e/0x60 [i915]
> [  241.354333]  [<c1002122>] do_one_initcall+0xd2/0x190
> [  241.354352]  [<c10e94f8>] ? tracepoint_module_notify+0x118/0x180
> [  241.354372]  [<f8655000>] ? 0xf8654fff
> [  241.354389]  [<c1049daf>] ? set_memory_nx+0x5f/0x70
> [  241.354411]  [<c16393ee>] ? set_section_ro_nx+0x54/0x59
> [  241.354432]  [<c10c210a>] load_module+0x111a/0x18e0
> [  241.354464]  [<c10c2a35>] SyS_finit_module+0x75/0xc0
> [  241.354481]  [<c11374cb>] ? vm_mmap_pgoff+0x7b/0xa0
> [  241.354513]  [<c164b90d>] sysenter_do_call+0x12/0x28

> I'll test the drm-intel-nightly next</span >

For reference that looks to be fixed with

commit 7ad228b11ec26a820291c9f5a1168d6176580dc1
Author: Ville Syrjälä <<a href="mailto:ville.syrjala@linux.intel.com">ville.syrjala@linux.intel.com</a>>
Date:   Tue Jan 7 16:15:36 2014 +0200

    drm/i915: Don't grab crtc mutexes in intel_modeset_gem_init()

    When the pipe A force quirk is applied the code will attempt to grab
    a crtc mutex during intel_modeset_setup_hw_state(). If we're already
    holding all crtc mutexes this will obviously deadlock every time.

    So instead of using drm_modeset_lock_all() just grab the
    mode_config.mutex. This is enough to avoid the unlocked mutex warnings
    from certain lower level functions.

    The regression was introduced in:

     commit 027476642811f8559cbe00ef6cc54db230e48a20
     Author: Ville Syrjälä <<a href="mailto:ville.syrjala@linux.intel.com">ville.syrjala@linux.intel.com</a>>
     Date:   Mon Dec 2 11:08:06 2013 +0200

        drm/i915: Take modeset locks around intel_modeset_setup_hw_state()

    Signed-off-by: Ville Syrjälä <<a href="mailto:ville.syrjala@linux.intel.com">ville.syrjala@linux.intel.com</a>>
    Cc: <a href="mailto:stable@vger.kernel.org">stable@vger.kernel.org</a>
    [danvet: Add cc: stable since the offending commit has that, too.]
    Signed-off-by: Daniel Vetter <<a href="mailto:daniel.vetter@ffwll.ch">daniel.vetter@ffwll.ch</a>></pre>
        </div>
      </p>
      <hr>
      <span>You are receiving this mail because:</span>
      
      <ul>
          <li>You are the QA Contact for the bug.</li>
          <li>You are on the CC list for the bug.</li>
          <li>You are the assignee for the bug.</li>
      </ul>
    </body>
</html>