From: Jesse Barnes Date: Mon, 5 Apr 2010 21:03:51 +0000 (-0700) Subject: drm/i915: don't queue flips during a flip pending event X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=83f7fd055eb3f1e843803cd906179d309553967b;p=linux.git drm/i915: don't queue flips during a flip pending event Hardware will set the flip pending ISR bit as soon as it receives the flip instruction, and (supposedly) clear it once the flip completes (e.g. at the next vblank). If we try to send down a flip instruction while the ISR bit is set, the hardware can become very confused, and we may never receive the corresponding flip pending interrupt, effectively hanging the chip. Signed-off-by: Jesse Barnes Signed-off-by: Eric Anholt --- diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index fdeff43537257..dc65a1de5f020 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -4680,6 +4680,7 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc, unsigned long flags; int pipesrc_reg = (intel_crtc->pipe == 0) ? PIPEASRC : PIPEBSRC; int ret, pipesrc; + u32 flip_mask; work = kzalloc(sizeof *work, GFP_KERNEL); if (work == NULL) @@ -4733,6 +4734,16 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc, atomic_inc(&obj_priv->pending_flip); work->pending_flip_obj = obj; + if (intel_crtc->plane) + flip_mask = I915_DISPLAY_PLANE_B_FLIP_PENDING_INTERRUPT; + else + flip_mask = I915_DISPLAY_PLANE_A_FLIP_PENDING_INTERRUPT; + + /* Wait for any previous flip to finish */ + if (IS_GEN3(dev)) + while (I915_READ(ISR) & flip_mask) + ; + BEGIN_LP_RING(4); OUT_RING(MI_DISPLAY_FLIP | MI_DISPLAY_FLIP_PLANE(intel_crtc->plane));