Bug 93608 - bisected: i915 SNB modeset crash in ac9b8236551d1177fd07b56aef9b565d1864420d
Summary: bisected: i915 SNB modeset crash in ac9b8236551d1177fd07b56aef9b565d1864420d
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/Intel (show other bugs)
Version: unspecified
Hardware: x86-64 (AMD64) Linux (All)
: medium normal
Assignee: Intel GFX Bugs mailing list
QA Contact: Intel GFX Bugs mailing list
Depends on:
Reported: 2016-01-06 15:40 UTC by Meelis Roos
Modified: 2017-07-24 22:43 UTC (History)
1 user (show)

See Also:
i915 platform: SNB
i915 features:

good dmesg with debug (85.05 KB, text/plain)
2016-01-06 15:40 UTC, Meelis Roos
no flags Details
bad dmesg with debug (40.18 KB, text/plain)
2016-01-06 15:41 UTC, Meelis Roos
no flags Details

Description Meelis Roos 2016-01-06 15:40:51 UTC
Created attachment 120833 [details]
good dmesg with debug

This is a followon to meiling list bug report with subject
bisected: i915 modeset broken in ac9b8236551d1177fd07b56aef9b565d1864420d

Between 4.4-rc3 and 4.4-rc4, i915 modesetting broke on my i5-2400 PC. 
Instead of seeing the new dense graphics mode, I see the last VGA text 
lines and no X appears either.

I saw something similar on I865G but have not had time to check if it is 
the same issue.

ac9b8236551d1177fd07b56aef9b565d1864420d is the first bad commit
commit ac9b8236551d1177fd07b56aef9b565d1864420d
Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date:   Fri Nov 27 18:55:26 2015 +0200

    drm/i915: Introduce a gmbus power domain
    Currently the gmbus code uses intel_aux_display_runtime_get/put in an
    effort to make sure the hardware is powered up sufficiently for gmbus.
    That function only takes the runtime PM reference which on VLV/CHV/BXT
    is not enough. We need the disp2d/pipe-a well on VLV/CHV and power well
    2 on BXT. So add a new power domnain for gmbus and kill off the now
    unused intel_aux_display_runtime_get/put. And change
    intel_hdmi_set_edid() to use the gmbus power domain too since that's all
    we need there.
    Also toss in a BUILD_BUG_ON() to catch problems if we run out of
    bits for power domains. We're already really close to the limit...
    [Patrik: Add gmbus string to debugfs output]
    Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
    Reviewed-by: Patrik Jakobsson <patrik.jakobsson@linux.intel.com>
    [Cherry-picked from drm-intel-next-queued f0ab43e6 (Imre)]
    Signed-off-by: Imre Deak <imre.deak@intel.com>
    Link: http://patchwork.freedesktop.org/patch/msgid/1448643329-18675-3-git-send-email-imre.deak@intel.com
    Signed-off-by: Jani Nikula <jani.nikula@intel.com>

:040000 040000 39379146d7e6dda8a4d5f8781ee3d307cce8c47e f4f09fae0485ad6263d31d425296fa9cd7de343b M     drivers

As per Ville Syrjäläs suggestion, attached are boot logs with drm.debug=0xe.

Monitor is connected via DVI.
Comment 1 Meelis Roos 2016-01-06 15:41:36 UTC
Created attachment 120834 [details]
bad dmesg with debug
Comment 3 Chris Wilson 2016-03-27 16:12:03 UTC
commit f5949141a21ee16edf1beaf95cbae7e419171ab5
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Wed Jan 13 11:55:28 2016 +0100

    drm/i915: Init power domains early in driver load

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