diff options
| -rw-r--r-- | drivers/gpu/drm/i915/intel_display.c | 9 | ||||
| -rw-r--r-- | drivers/gpu/drm/i915/intel_sprite.c | 21 |
2 files changed, 30 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 3cabe52a4e3b..569717a12723 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -12203,6 +12203,15 @@ static void update_scanline_offset(struct intel_crtc *crtc) * type. For DP ports it behaves like most other platforms, but on HDMI * there's an extra 1 line difference. So we need to add two instead of * one to the value. + * + * On VLV/CHV DSI the scanline counter would appear to increment + * approx. 1/3 of a scanline before start of vblank. Unfortunately + * that means we can't tell whether we're in vblank or not while + * we're on that particular line. We must still set scanline_offset + * to 1 so that the vblank timestamps come out correct when we query + * the scanline counter from within the vblank interrupt handler. + * However if queried just before the start of vblank we'll get an + * answer that's slightly in the future. */ if (IS_GEN2(dev_priv)) { const struct drm_display_mode *adjusted_mode = &crtc->config->base.adjusted_mode; diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c index 8c87c717c7cd..e6517edcd16b 100644 --- a/drivers/gpu/drm/i915/intel_sprite.c +++ b/drivers/gpu/drm/i915/intel_sprite.c @@ -83,10 +83,13 @@ int intel_usecs_to_scanlines(const struct drm_display_mode *adjusted_mode, */ void intel_pipe_update_start(struct intel_crtc *crtc) { + struct drm_i915_private *dev_priv = to_i915(crtc->base.dev); const struct drm_display_mode *adjusted_mode = &crtc->config->base.adjusted_mode; long timeout = msecs_to_jiffies_timeout(1); int scanline, min, max, vblank_start; wait_queue_head_t *wq = drm_crtc_vblank_waitqueue(&crtc->base); + bool need_vlv_dsi_wa = (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) && + intel_crtc_has_type(crtc->config, INTEL_OUTPUT_DSI); DEFINE_WAIT(wait); vblank_start = adjusted_mode->crtc_vblank_start; @@ -139,6 +142,24 @@ void intel_pipe_update_start(struct intel_crtc *crtc) drm_crtc_vblank_put(&crtc->base); + /* + * On VLV/CHV DSI the scanline counter would appear to + * increment approx. 1/3 of a scanline before start of vblank. + * The registers still get latched at start of vblank however. + * This means we must not write any registers on the first + * line of vblank (since not the whole line is actually in + * vblank). And unfortunately we can't use the interrupt to + * wait here since it will fire too soon. We could use the + * frame start interrupt instead since it will fire after the + * critical scanline, but that would require more changes + * in the interrupt code. So for now we'll just do the nasty + * thing and poll for the bad scanline to pass us by. + * + * FIXME figure out if BXT+ DSI suffers from this as well + */ + while (need_vlv_dsi_wa && scanline == vblank_start) + scanline = intel_get_crtc_scanline(crtc); + crtc->debug.scanline_start = scanline; crtc->debug.start_vbl_time = ktime_get(); crtc->debug.start_vbl_count = intel_crtc_get_vblank_counter(crtc); |