[Intel-gfx] bisected: i915 modeset broken in ac9b8236551d1177fd07b56aef9b565d1864420d

[Meelis Roos]

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 at 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 at linux.intel.com>
    Reviewed-by: Patrik Jakobsson <patrik.jakobsson at linux.intel.com>
    [Cherry-picked from drm-intel-next-queued f0ab43e6 (Imre)]
    Signed-off-by: Imre Deak <imre.deak at 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 at intel.com>

:040000 040000 39379146d7e6dda8a4d5f8781ee3d307cce8c47e f4f09fae0485ad6263d31d425296fa9cd7de343b M     drivers


-- 
Meelis Roos (mroos at linux.ee)