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    drm/i915: implement drmmode overlay support v4 · 02e792fb
    Daniel Vetter 提交于
    This implements intel overlay support for kms via a device-specific
    ioctl. Thomas Hellstrom brought up the idea of a general ioctl (on
    dri-devel). We've reached the conclusion that such an infrastructure
    only makes sense when multiple kms overlay implementations exists,
    which atm don't (and it doesn't look like this is gonna change).
    
    Open issues:
    - Runs in sync with the gpu, i.e. unnecessary waiting. I've decided
      to wait on this because the hw tends to hang when changing something
      in this area. I left some dummy functions as infrastructure.
    - polyphase filtering uses a static table.
    - uses uninterruptible sleeps. Unfortunately the alternatives may
      unnecessarily wedged the hw if/when we timeout too early (and
      userspace only overloaded the batch buffers with stuff worth a few
      secs of gpu time).
    
    Changes since v1:
    - fix off-by-one misconception on my side. This fixes fullscreen
      playback.
    Changes since v2:
    - add underrun detection as spec'ed for i965.
    - flush caches properly, fixing visual corruptions.
    Changes since v4:
    - fix up cache flushing of overlay memory regs.
    - killed require_pipe_a logic - it hangs the chip.
    
    Tested-By: diego.abelenda@gmail.com (on a 865G)
    Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
    [anholt: Resolved against the MADVISE ioctl going in before this one]
    Signed-off-by: NEric Anholt <eric@anholt.net>
    02e792fb
i915_dma.c 43.7 KB