1. 06 May, 2014 1 commit
    • Ville Syrjälä's avatar
      drm/i915: Make sprite updates atomic · 8d7849db
      Ville Syrjälä authored
      Add a mechanism by which we can evade the leading edge of vblank. This
      guarantees that no two sprite register writes will straddle on either
      side of the vblank start, and that means all the writes will be latched
      together in one atomic operation.
      
      We do the vblank evade by checking the scanline counter, and if it's too
      close to the start of vblank (too close has been hardcoded to 100usec
      for now), we will wait for the vblank start to pass. In order to
      eliminate random delayes from the rest of the system, we operate with
      interrupts disabled, except when waiting for the vblank obviously.
      
      Note that we now go digging through pipe_to_crtc_mapping[] in the
      vblank interrupt handler, which is a bit dangerous since we set up
      interrupts before the crtcs. However in this case since it's the vblank
      interrupt, we don't actually unmask it until some piece of code
      requests it.
      
      v2: preempt_check_resched() calls after local_irq_enable() (Jesse)
          Hook up the vblank irq stuff on BDW as well
      v3: Pass intel_crtc instead of drm_crtc (Daniel)
          Warn if crtc.mutex isn't locked (Daniel)
          Add an explicit compiler barrier and document the barriers (Daniel)
          Note the irq vs. modeset setup madness in the commit message (Daniel)
      v4: Use prepare_to_wait() & co. directly and eliminate vbl_received
      v5: Refactor intel_pipe_handle_vblank() vs. drm_handle_vblank() (Chris)
          Check for min/max scanline <= 0 (Chris)
          Don't call intel_pipe_update_end() if start failed totally (Chris)
          Check that the vblank counters match on both sides of the critical
          section (Chris)
      v6: Fix atomic update for interlaced modes
      v7: Reorder code for better readability (Chris)
      v8: Drop preempt_check_resched(). It's not available to modules
          anymore and isn't even needed unless we ourselves cause
          a wakeup needing reschedule while interrupts are off
      Reviewed-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
      Reviewed-by: default avatarSourab Gupta <sourabgupta@gmail.com>
      Reviewed-by: default avatarAkash Goel <akash.goels@gmail.com>
      Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
      Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      8d7849db
  2. 05 May, 2014 39 commits