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<base href="https://bugs.freedesktop.org/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - i915 does 2s long DP-link-reset (backlight off) during modeset instead of re-using SimpleFB, stacktrace with i915.fastboot=1"
href="https://bugs.freedesktop.org/show_bug.cgi?id=91845">91845</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>i915 does 2s long DP-link-reset (backlight off) during modeset instead of re-using SimpleFB, stacktrace with i915.fastboot=1
</td>
</tr>
<tr>
<th>Product</th>
<td>DRI
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Hardware</th>
<td>x86-64 (AMD64)
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux (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>DRM/Intel
</td>
</tr>
<tr>
<th>Assignee</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>o.freyermuth@googlemail.com
</td>
</tr>
<tr>
<th>QA Contact</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>CC</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr></table>
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<div>
<pre>Created <span class=""><a href="attachment.cgi?id=118043" name="attach_118043" title="dmesg from boot with: "pcie_aspm=force i915.fastboot=1 drm.debug=0x06"">attachment 118043</a> <a href="attachment.cgi?id=118043&action=edit" title="dmesg from boot with: "pcie_aspm=force i915.fastboot=1 drm.debug=0x06"">[details]</a></span>
dmesg from boot with: "pcie_aspm=force i915.fastboot=1 drm.debug=0x06"
Bug description:
System is EFI-booted (via refind), efifb with native resolution is available.
During modeset, display backlight is turned off for ~2 s, drm.debug=0x06
reveals DP and panel are fully reset.
Forcing i915.fastboot=1 produces the following messages (from attached dmesg):
...
[ 0.528989] [drm:intel_fbdev_init_bios] using BIOS fb for initial console
...
[ 0.602811] [drm:intelfb_create] re-using BIOS fb
...
i.e. all fine, but then:
...
[ 0.611868] [drm:intel_edp_backlight_off]
...
...
[ 1.813729] [drm:intel_panel_actually_set_backlight] set backlight PWM = 0
[ 1.825971] [drm:edp_panel_off] Turn eDP port A panel power off
[ 1.825977] [drm:wait_panel_off] Wait for panel power off time
[ 2.868867] [drm:intel_psr_enable] PSR not supported by this panel
[ 2.868868] [drm:intel_edp_drrs_enable] Panel doesn't support DRRS
[ 2.868876] ------------[ cut here ]------------
[ 2.868882] WARNING: CPU: 7 PID: 36 at
drivers/gpu/drm/i915/intel_uncore.c:620 hsw_unclaimed_reg_debug+0x65/0x7e()
[ 2.868885] [drm:intel_uncore_check_errors] *ERROR* Unclaimed register
before interrupt
[ 2.868886] Unclaimed register detected after writing to register 0x68070
[ 2.868887] Modules linked in:
[ 2.868890] CPU: 7 PID: 36 Comm: kworker/7:0 Not tainted 4.2.0-gentoo #4
[ 2.868891] Hardware name: Clevo W230SD /powered by
premamod.com, BIOS 1.03.04PM v1 07/09/2015
[ 2.868895] Workqueue: events output_poll_execute
[ 2.868897] 0000000000000009 ffff88041db639f8 ffffffff8191b0a0
0000000000000001
[ 2.868899] ffff88041db63a48 ffff88041db63a38 ffffffff81052be9
ffff88041db63a38
[ 2.868901] ffffffff8156bd36 ffff88041ae80000 0000000000068070
ffff88041ae80080
[ 2.868902] Call Trace:
[ 2.868906] [<ffffffff8191b0a0>] dump_stack+0x45/0x57
[ 2.868910] [<ffffffff81052be9>] warn_slowpath_common+0x9c/0xb6
[ 2.868912] [<ffffffff8156bd36>] ? hsw_unclaimed_reg_debug+0x65/0x7e
[ 2.868914] [<ffffffff81052c44>] warn_slowpath_fmt+0x41/0x43
[ 2.868917] [<ffffffff81082972>] ? arch_local_irq_save+0x15/0x1b
[ 2.868919] [<ffffffff8156bd36>] hsw_unclaimed_reg_debug+0x65/0x7e
[ 2.868921] [<ffffffff8156edfa>] hsw_write32+0xa8/0xca
[ 2.868924] [<ffffffff8157b99e>] intel_update_pipe_size+0xef/0x145
[ 2.868926] [<ffffffff8157ba51>] intel_commit_primary_plane+0x5d/0x83
[ 2.868929] [<ffffffff8159811a>] intel_plane_atomic_update+0x14/0x16
[ 2.868932] [<ffffffff8150bde2>]
drm_atomic_helper_commit_planes_on_crtc+0x112/0x166
[ 2.868934] [<ffffffff81582c63>] __intel_set_mode+0x8b5/0x8e1
[ 2.868937] [<ffffffff81588954>] intel_crtc_set_config+0x3fb/0x4c0
[ 2.868940] [<ffffffff8151b536>] drm_mode_set_config_internal+0x57/0xe3
[ 2.868942] [<ffffffff8150c847>] restore_fbdev_mode+0xb5/0xcf
[ 2.868944] [<ffffffff8150e155>]
drm_fb_helper_restore_fbdev_mode_unlocked+0x22/0x59
[ 2.868946] [<ffffffff8150e1bd>] drm_fb_helper_set_par+0x31/0x35
[ 2.868948] [<ffffffff8150e12c>] drm_fb_helper_hotplug_event+0xa6/0xad
[ 2.868950] [<ffffffff81595623>] intel_fbdev_output_poll_changed+0x19/0x1b
[ 2.868952] [<ffffffff815050d6>] drm_kms_helper_hotplug_event+0x23/0x27
[ 2.868954] [<ffffffff8150522d>] output_poll_execute+0x12d/0x14e
[ 2.868956] [<ffffffff810950d6>] ? lock_timer_base.isra.33+0x42/0x68
[ 2.868958] [<ffffffff81095a58>] ? mod_timer+0x7c/0x83
[ 2.868961] [<ffffffff81065375>] process_one_work+0x152/0x272
[ 2.868963] [<ffffffff8106591c>] worker_thread+0x1eb/0x29a
[ 2.868966] [<ffffffff81065731>] ? rescuer_thread+0x272/0x272
[ 2.868968] [<ffffffff810697fe>] kthread+0xa0/0xa8
[ 2.868970] [<ffffffff8106975e>] ? kthread_parkme+0x1f/0x1f
[ 2.868973] [<ffffffff81921d5f>] ret_from_fork+0x3f/0x70
[ 2.868975] [<ffffffff8106975e>] ? kthread_parkme+0x1f/0x1f
[ 2.868976] ---[ end trace abe6cc7ab4fd79a7 ]---
[ 2.868989] [drm:intel_uncore_check_errors] *ERROR* Unclaimed register
before interrupt
Stacktrace not observed without i915.fastboot=1, but the 2 seconds with
backlight off during boot are always there (supposedly prolonging the overall
boot time significantly).
System environment:
-- Gentoo Linux 4.2.0 x86_64
-- Machine: Clevo W230SD (Schenker XMG A305)
-- Display connector: Internal Panel, DP connected
Additional info:
-- Machine has nVidia Optimus (should not be relevant here)</pre>
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