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-rw-r--r--drivers/gpu/drm/i915/intel_display.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 20e99a0c55366..9c87d5784f1a8 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2151,6 +2151,17 @@ static void intel_enable_pipe(struct intel_crtc *crtc)
I915_WRITE(reg, val | PIPECONF_ENABLE);
POSTING_READ(reg);
+
+ /*
+ * Until the pipe starts DSL will read as 0, which would cause
+ * an apparent vblank timestamp jump, which messes up also the
+ * frame count when it's derived from the timestamps. So let's
+ * wait for the pipe to start properly before we call
+ * drm_crtc_vblank_on()
+ */
+ if (dev->max_vblank_count == 0 &&
+ wait_for(intel_get_crtc_scanline(crtc) != crtc->scanline_offset, 50))
+ DRM_ERROR("pipe %c didn't start\n", pipe_name(pipe));
}
/**