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<base href="https://bugs.freedesktop.org/" />
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Priority</th>
<td>medium
</td>
</tr>
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [HSW bisected]igt/testdisplay cause Call Trace with : WARNING: CPU: 2 PID: 16 at drivers/gpu/drm/i915/intel_display.c:6863 hsw_enable_pc8+0x111/0x626 [i915]()"
href="https://bugs.freedesktop.org/show_bug.cgi?id=76880">76880</a>
</td>
</tr>
<tr>
<th>CC</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Assignee</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Summary</th>
<td>[HSW bisected]igt/testdisplay cause Call Trace with : WARNING: CPU: 2 PID: 16 at drivers/gpu/drm/i915/intel_display.c:6863 hsw_enable_pc8+0x111/0x626 [i915]()
</td>
</tr>
<tr>
<th>QA Contact</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Reporter</th>
<td>lei.a.liu@intel.com
</td>
</tr>
<tr>
<th>Hardware</th>
<td>Other
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Component</th>
<td>DRM/Intel
</td>
</tr>
<tr>
<th>Product</th>
<td>DRI
</td>
</tr></table>
<p>
<div>
<pre>System Environment:
--------------------------
Platform: Haswell
Kernel: drm-intel-next-queued(243ee1643b4c37ef00bb1f3cb3e67cc021690344)
Bug detailed description:
-----------------------------
While doing testdisplay -a with VGA, VGA flashed (i attach a video for more
detail　URL:<a href="http://youtu.be/-sdoFvv9Skk">http://youtu.be/-sdoFvv9Skk</a> ).And we can find the Call Trace in
dmesg:
Call Trace:
------------[ cut here ]------------
[ 37.741923] WARNING: CPU: 2 PID: 16 at
drivers/gpu/drm/i915/intel_display.c:6864 hsw_enable_pc8+0x134/0x626 [i915]()
[ 37.741924] SPLL enabled
[ 37.741925] Modules linked in: dm_mod pcspkr snd_hda_codec_realtek
snd_hda_codec_generic i2c_i801 snd_hda_codec_hdmi iTCO_wdt iTCO_vendor_support
lpc_ich mfd_core snd_hda_intel snd_hda_codec snd_hwdep snd_pcm snd_timer snd
soundcore battery ppdev parport_pc parport ac acpi_cpufreq i915 video button
drm_kms_helper drm
[ 37.741933] CPU: 2 PID: 16 Comm: kworker/2:0 Tainted: G W
3.14.0_drm-intel-next-queued_44b65c_20140401+ #1234
[ 37.741933] Hardware name: Intel Corporation Shark Bay Client
platform/SthiPpvRsvd2, BIOS HSWLPTU1.86C.0134.R00.1310022130 10/02/2013
[ 37.741935] Workqueue: pm pm_runtime_work
[ 37.741935] 0000000000000000 0000000000000009 ffffffff81717233
ffff88043bdbfc88
[ 37.741937] ffffffff81035052 ffffc90012644024 ffffffffa009ed05
0000000000000000
[ 37.741938] ffff8804369b0000 ffff88009e0d9b38 ffff88009e0d9b40
ffff88043bb68098
[ 37.741939] Call Trace:
[ 37.741941] [<ffffffff81717233>] ? dump_stack+0x41/0x51
[ 37.741942] [<ffffffff81035052>] ? warn_slowpath_common+0x73/0x8b
[ 37.741947] [<ffffffffa009ed05>] ? hsw_enable_pc8+0x134/0x626 [i915]
[ 37.741948] [<ffffffff81035102>] ? warn_slowpath_fmt+0x45/0x4a
[ 37.741953] [<ffffffffa008df9c>] ? gen6_read32+0x76/0x81 [i915]
[ 37.741958] [<ffffffffa009ed05>] ? hsw_enable_pc8+0x134/0x626 [i915]
[ 37.741962] [<ffffffffa00600f3>] ? i915_runtime_suspend+0x62/0xb1 [i915]
[ 37.741964] [<ffffffff812f8968>] ? pci_pm_runtime_suspend+0x60/0x119
[ 37.741965] [<ffffffff8138406e>] ? __rpm_callback+0x28/0x4c
[ 37.741966] [<ffffffff813840dd>] ? rpm_callback+0x4b/0x69
[ 37.741967] [<ffffffff81384689>] ? rpm_suspend+0x2a9/0x3f9
[ 37.741969] [<ffffffff8103c75e>] ? internal_add_timer+0xd/0x28
[ 37.741970] [<ffffffff8103cf3f>] ? mod_timer+0x125/0x13d
[ 37.741971] [<ffffffff81385329>] ? pm_runtime_work+0x65/0x7b
[ 37.741973] [<ffffffff81046660>] ? process_one_work+0x1bc/0x2ed
[ 37.741974] [<ffffffff81046bce>] ? worker_thread+0x1c7/0x2bc
[ 37.741976] [<ffffffff81046a07>] ? rescuer_thread+0x251/0x251
[ 37.741977] [<ffffffff8104b53e>] ? kthread+0xc5/0xcd
[ 37.741979] [<ffffffff8104b479>] ? kthread_freezable_should_stop+0x40/0x40
[ 37.741981] [<ffffffff817217fc>] ? ret_from_fork+0x7c/0xb0
[ 37.741983] [<ffffffff8104b479>] ? kthread_freezable_should_stop+0x40/0x40
[ 37.741984] ---[ end trace 53debec2e22c7e47 ]---
Reproduce steps:
----------------------------
1. ./testdisplay -a (using IGT )
2. xinit & ; chvt 1 (this method is more effective to reproduce)
first bad commit:
----------------------------
commit a8a8bd547e6323c56295e1c5a03e30e765d42325
Author: Paulo Zanoni <<a href="mailto:paulo.r.zanoni@intel.com">paulo.r.zanoni@intel.com</a>>
Date: Fri Mar 7 20:08:05 2014 -0300
drm/i915: make PC8 be part of runtime PM suspend/resume</pre>
</div>
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