From: Tom O'Rourke <Tom.O'Rourke@xxxxxxxxx>
The efficient frequency (RPe) should stay in the range
RPn <= RPe <= RP0. The pcode clamps the returned value
internally on Broadwell but not on Haswell.
Fix for missing range check in
commit 93ee29203f506582cca2bcec5f05041526d9ab0a
Author: Tom O'Rourke <Tom.O'Rourke@xxxxxxxxx>
Date: Wed Nov 19 14:21:52 2014 -0800
drm/i915: Use efficient frequency for HSW/BDW
Reference: http://lists.freedesktop.org/archives/intel-gfx/2015-February/059802.html
Reported-by: Michael Auchter <a@xxxxxxxxx>
Suggested-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Tom O'Rourke <Tom.O'Rourke@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_pm.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index a3b979d..602c443 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3998,7 +3998,10 @@ static void gen6_init_rps_frequencies(struct drm_device *dev)
&ddcc_status);
if (0 == ret)
dev_priv->rps.efficient_freq =
- (ddcc_status >> 8) & 0xff;
+ clamp_t(u8,
+ ((ddcc_status >> 8) & 0xff),
+ dev_priv->rps.min_freq,
+ dev_priv->rps.max_freq);
}
/* Preserve min/max settings in case of re-init */
--
1.7.9.5
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