diff mbox

drm/i915: increase default latency constant

Message ID 20090818123313.0a95baca@jbarnes-g45 (mailing list archive)
State Superseded
Headers show

Commit Message

Jesse Barnes Aug. 18, 2009, 7:33 p.m. UTC 
Some i915/i945 platforms have a fairly high memory latency in certain
situations, so increase our constant a bit to avoid FIFO underruns.
The effect should be positive on other platforms as well; we'll have a
bit more insurance against a busy memory subsystem due to the extra
FIFO entries.

Fixes fdo bug #23368.

Tested-by: Sven Arvidsson <sa@whiz.se>
Tested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

Comments

Jesse Barnes Aug. 28, 2009, 5:17 p.m. UTC | #1 
On Tue, 18 Aug 2009 12:33:13 -0700
Jesse Barnes <jbarnes@virtuousgeek.org> wrote:

> Some i915/i945 platforms have a fairly high memory latency in certain
> situations, so increase our constant a bit to avoid FIFO underruns.
> The effect should be positive on other platforms as well; we'll have a
> bit more insurance against a busy memory subsystem due to the extra
> FIFO entries.
> 
> Fixes fdo bug #23368.

FYI Eric, this has been biting a few users with low end configs; so I
think it should go into 2.6.31.
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index d6fce21..80c9473 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2005,7 +2005,7 @@  static void igd_enable_cxsr(struct drm_device *dev, unsigned long clock,
 	return;
 }
 
-const static int latency_ns = 3000; /* default for non-igd platforms */
+const static int latency_ns = 5000; /* default for non-igd platforms */
 
 static int intel_get_fifo_size(struct drm_device *dev, int plane)
 {