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-rw-r--r--drivers/gpu/drm/i915/i915_irq.c23
1 files changed, 22 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 9fec71175571..d4c952d12f3b 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -702,7 +702,28 @@ static int i915_get_crtc_scanoutpos(struct drm_device *dev, int pipe,
else
position = __raw_i915_read32(dev_priv, PIPEDSL(pipe)) & DSL_LINEMASK_GEN3;
- if (HAS_PCH_SPLIT(dev)) {
+ if (HAS_DDI(dev)) {
+ /*
+ * On HSW HDMI outputs there seems to be a 2 line
+ * difference, whereas eDP has the normal 1 line
+ * difference that earlier platforms have. External
+ * DP is unknown. For now just check for the 2 line
+ * difference case on all output types on HSW+.
+ *
+ * This might misinterpret the scanline counter being
+ * one line too far along on eDP, but that's less
+ * dangerous than the alternative since that would lead
+ * the vblank timestamp code astray when it sees a
+ * scanline count before vblank_start during a vblank
+ * interrupt.
+ */
+ in_vbl = ilk_pipe_in_vblank_locked(dev, pipe);
+ if ((in_vbl && (position == vbl_start - 2 ||
+ position == vbl_start - 1)) ||
+ (!in_vbl && (position == vbl_end - 2 ||
+ position == vbl_end - 1)))
+ position = (position + 2) % vtotal;
+ } else if (HAS_PCH_SPLIT(dev)) {
/*
* The scanline counter increments at the leading edge
* of hsync, ie. it completely misses the active portion