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      <base href="https://bugs.freedesktop.org/" />
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    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - Recent change makes Xorg hangs"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=94685">94685</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Recent change makes Xorg hangs
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>xorg
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>git
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>Other
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>All
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>normal
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>medium
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>Driver/intel
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>chris@chris-wilson.co.uk
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>alexandre.nunes@gmail.com
          </td>
        </tr>

        <tr>
          <th>QA Contact</th>
          <td>intel-gfx-bugs@lists.freedesktop.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>I've traced this too 02f535e8f3659f1147c6f2e698bd5d8730dec19b - after reversal
it was working again.

To reproduce, hover the mouse over a recent kde5 menu and Xorg hangs in an
infinite loop.

Connecting via ssh I was able to ask gdb for this live backtrace:

#0  0x00007f3b82cde577 in ioctl () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007f3b83faf558 in drmIoctl ()
   from /usr/lib/x86_64-linux-gnu/libdrm.so.2
#2  0x00007f3b7e6e32da in sna_present_queue ()
   from /usr/lib/xorg/modules/drivers/intel_drv.so
#3  0x00007f3b7e6e3448 in vblank_complete ()
   from /usr/lib/xorg/modules/drivers/intel_drv.so
#4  0x00007f3b7e6e395e in sna_present_vblank_handler ()
   from /usr/lib/xorg/modules/drivers/intel_drv.so
#5  0x00007f3b7e65109c in sna_mode_wakeup ()
   from /usr/lib/xorg/modules/drivers/intel_drv.so
#6  0x00007f3b7e654c10 in sna_wakeup_handler ()
   from /usr/lib/xorg/modules/drivers/intel_drv.so
#7  0x000055999747577a in WakeupHandler ()
#8  0x00005599975cbbaf in WaitForSomething ()
#9  0x00005599974709ce in ?? ()
#10 0x0000559997474bb3 in ?? ()
#11 0x00007f3b82c1d610 in __libc_start_main (main=0x55999745ef10, argc=8, 
    argv=0x7ffca32f6918, init=<optimized out>, fini=<optimized out>, 
    rtld_fini=<optimized out>, stack_end=0x7ffca32f6908) at libc-start.c:291
#12 0x000055999745ef49 in _start ()

lspci reports 00:02.0 VGA compatible controller: Intel Corporation 2nd
Generation Core Processor Family Integrated Graphics Controller (rev 09)

It's a Intel(R) Core(TM) i5-2410M system and the Xorg log reports:
[  1972.493] (II) intel: Driver for Intel(R) HD Graphics: 2000-6000
[  1972.493] (II) intel: Driver for Intel(R) Iris(TM) Graphics: 5100, 6100
[  1972.493] (II) intel: Driver for Intel(R) Iris(TM) Pro Graphics: 5200, 6200,
P6300
[  1972.493] (II) intel(0): Using Kernel Mode Setting driver: i915, version
1.6.0 20151010
[  1972.493] (II) intel(0): SNA compiled from 2.99.917-581-g1b82b7b
[  1972.493] (--) intel(0): Integrated Graphics Chipset: Intel(R) HD Graphics
3000
[  1972.493] (--) intel(0): CPU: x86-64, sse2, sse3, ssse3, sse4.1, sse4.2,
avx; using a maximum of 2 threads
[  1972.493] (II) intel(0): Creating default Display subsection in Screen
section</pre>
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