• Daniel Vetter's avatar
    drm/i915: prefer VBT modes for SVDO-LVDS over EDID · c3456fb3
    Daniel Vetter authored
    In
    
    commit 53d3b4d7
    Author: Egbert Eich <eich@suse.de>
    Date:   Tue Jun 4 17:13:21 2013 +0200
    
        drm/i915/sdvo: Use &intel_sdvo->ddc instead of intel_sdvo->i2c for DDC
    
    Egbert Eich fixed a long-standing bug where we simply used a
    non-working i2c controller to read the EDID for SDVO-LVDS panels.
    Unfortunately some machines seem to not be able to cope with the mode
    provided in the EDID. Specifically they seem to not be able to cope
    with a 4x pixel mutliplier instead of a 2x one, which seems to have
    been worked around by slightly changing the panels native mode in the
    VBT so that the dotclock is just barely above 50MHz.
    
    Since it took forever to notice the breakage it's fairly safe to
    assume that at least for SDVO-LVDS panels the VBT contains fairly sane
    data. So just switch around the order and use VBT modes first.
    
    v2: Also add EDID modes just in case, and spell Egbert correctly.
    
    v3: Elaborate a bit more about what's going on on Chris' machine.
    
    Cc: Egbert Eich <eich@suse.de>
    Cc: Chris Wilson <chris@chris-wilson.co.uk>
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=65524
    Cc: stable@vger.kernel.org
    Reported-and-tested-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
    Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
    c3456fb3
intel_sdvo.c 86.7 KB