• Rodrigo Vivi's avatar
    drm/i915: Kill sink_crc for good · 5fd9df6a
    Rodrigo Vivi authored
    It was originally introduced following the VESA spec in order to validate PSR.
    
    However we found so many issues around sink_crc that instead of helping PSR
    development it only brought another layer of trouble to the table.
    
    So, sink_crc has been a black whole for us in question of time, effort and hope.
    
    First of the problems is that HW statement is clear: "Do not attempt to use
    aux communication with PSR enabled". So the main reason behind sink_crc is
    already compromised.
    
    For a while we had hope on the aux-mutex could workaround this problem on SKL+
    platforms, but that mutex was not reliable, not tested,
    and we shouldn't use according to HW engineers.
    
    Also, nor source, nor sink designed and implemented the sink_crc to be used like
    we are trying to use here.
    
    Well, the sink side of things is also apparently not prepared for this
    case. Each panel that we tried seemed to have a different behavior with same
    code and same source.
    
    So, for all the time we lost on trying to ducktape all these different issues
    I believe it is now time to move PSR to a more reliable validation.
    Maybe not a perfect one as we dreamed for this sink_crc, but at least more
    reliable.
    
    Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
    Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
    Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
    Reviewed-by: default avatarDhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
    Link: https://patchwork.freedesktop.org/patch/msgid/20180705192528.30515-1-rodrigo.vivi@intel.com
    5fd9df6a
intel_drv.h 73.2 KB