[Intel-gfx] [PATCH] CHROMIUM: drm/i915: Adjust the down threshold.

[james.ausmus at intel.com]

From: Stéphane Marchesin <marcheu at chromium.org>

The thresholds for GPU reclocking are highly asymetrical. This creates an
interesting phenomenon on Chrome startup where the clock ramps up very
quickly, and then the blinking cursor is enough to keep it up. Obviously
having the max GPU clock on the login screen is very bad for thermals.

With this change, the clock goes back to its minimum frequency after a couple
of seconds.

BUG=chrome-os-partner:11009
TEST=checked that a blinking cursor lets the GPU clock go back to 350Mhz

Change-Id: I3b8de74864907abdb3c7c4aeb0ab4fcf2eaf0b2c
Reviewed-on: https://gerrit.chromium.org/gerrit/26641
Tested-by: Stéphane Marchesin <marcheu at chromium.org>
Reviewed-by: Sean Paul <seanpaul at chromium.org>
Reviewed-by: Sameer Nanda <snanda at chromium.org>
Commit-Ready: Stéphane Marchesin <marcheu at chromium.org>
[marcheu: Fixups for 3.8]
Signed-off-by: Stéphane Marchesin <marcheu at chromium.org>
---
 drivers/gpu/drm/i915/intel_pm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 3280cff..6d5e3ed 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -2612,7 +2612,7 @@ static void gen6_enable_rps(struct drm_device *dev)
 		   dev_priv->rps.min_delay << 16);
 
 	I915_WRITE(GEN6_RP_UP_THRESHOLD, 59400);
-	I915_WRITE(GEN6_RP_DOWN_THRESHOLD, 245000);
+	I915_WRITE(GEN6_RP_DOWN_THRESHOLD, 100000);
 	I915_WRITE(GEN6_RP_UP_EI, 66000);
 	I915_WRITE(GEN6_RP_DOWN_EI, 350000);
 
-- 
1.8.3.2