[PATCH] Lower threshold for pixel doubling.

* [PATCH] Lower threshold for pixel doubling.
@ 2013-05-20 18:15 Stuart Abercrombie
  2013-05-28 17:39 ` Stuart Abercrombie
  2013-08-16  8:20 ` Chris Wilson
  0 siblings, 2 replies; 13+ messages in thread
From: Stuart Abercrombie @ 2013-05-20 18:15 UTC (permalink / raw)
  To: intel-gfx

90% of core speed (=180MHz dot clock) is too high for 2048x1280 to get
pixel doubling on Pineview, which it needs to avoid underruns, so
lower this to 85%.

Signed-off-by: Stuart Abercrombie <sabercrombie@chromium.org>
---
 drivers/gpu/drm/i915/intel_display.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index efe8299..9c924e9 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4564,14 +4564,14 @@ static void i9xx_set_pipeconf(struct intel_crtc *intel_crtc)
 	pipeconf = I915_READ(PIPECONF(intel_crtc->pipe));
 
 	if (intel_crtc->pipe == 0 && INTEL_INFO(dev)->gen < 4) {
-		/* Enable pixel doubling when the dot clock is > 90% of the (display)
+		/* Enable pixel doubling when the dot clock is > 85% of the (display)
 		 * core speed.
 		 *
 		 * XXX: No double-wide on 915GM pipe B. Is that the only reason for the
 		 * pipe == 0 check?
 		 */
 		if (intel_crtc->config.requested_mode.clock >
-		    dev_priv->display.get_display_clock_speed(dev) * 9 / 10)
+		    dev_priv->display.get_display_clock_speed(dev) * 17 / 20)
 			pipeconf |= PIPECONF_DOUBLE_WIDE;
 		else
 			pipeconf &= ~PIPECONF_DOUBLE_WIDE;
-- 
1.8.2.1

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