• Chris Wilson's avatar
    drm/i915: Add comments to explain the BSD tail write workaround · 12f55818
    Chris Wilson authored
    Having had to dive into the bspec to understand what each stage of the
    workaround meant, and how that the ring broadcasting IDLE corresponded
    with the GT powering down the ring (i.e. rc6) add comments to aide
    the next reader.
    
    And since the register "is used to control all aspects of PSMI and power
    saving functions" that makes it quite interesting to inspect with
    regards to RC6 hangs, so add it to the error-state.
    
    v2: Rediscover the piece of magic, set the RNCID to 0 before waiting for
    the ring to wake up.
    Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
    Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
    12f55818
i915_irq.c 74.8 KB