On Monday 17 November 2014 06:11 PM, Ville Syrjälä wrote:
On Tue, Nov 18, 2014 at 05:59:07PM +0530, Deepak S wrote:
On Monday 17 November 2014 05:05 PM, Ville Syrjälä wrote:
On Tue, Nov 18, 2014 at 02:38:25PM +0530, Deepak S wrote:
On Tuesday 11 November 2014 02:25 AM, ville.syrj...@linux.intel.com wrote:
From: Ville Syrjälä <ville.syrj...@linux.intel.com>
Currently we miscalculate the GPU frequency on chv. This causes us to
report the GPU frequency as half of what it really is. Drop the extra
factor of 2 from the calculations to get the correct answer.
Signed-off-by: Ville Syrjälä <ville.syrj...@linux.intel.com>
---
drivers/gpu/drm/i915/intel_pm.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 03fbb45..74e4293 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -7329,7 +7329,7 @@ static int chv_gpu_freq(struct drm_i915_private
*dev_priv, int val)
if (div < 0)
return div;
- return DIV_ROUND_CLOSEST(czclk_freq * val, 2 * div) / 2;
+ return DIV_ROUND_CLOSEST(czclk_freq * val, 2 * div);
I think CHV is 2 X cck, shouldn't we report the cck freq and not 2 *cck?
Hmm. Once again the docs are extremely unclear. Dropping the 2x factor
gives me the same numbers that the tables in the docs have. But then
the spreadsheet calls it a "2x clock" in some places, which does suggest
it might get further divided down by 2.
Oh, now I did find a somewhat clear note in the clock HAS:
"The dedicated GPLL (Graphics PLL) sends a 2GHz gfx clock to GenLC,
which gets divided inside the GenLC block to derive a 1GHz Gfx fast clock."
So based on that the original code does make more sense.
Do we need to mention in comment about 2 * GFX clock?
Yeah, a comment would probably be a good idea. Could avoid some confusion
in the future if someone else looks at this code.
Will you add the comment and submit a patch?
}
static int chv_freq_opcode(struct drm_i915_private *dev_priv, int val)
@@ -7341,7 +7341,7 @@ static int chv_freq_opcode(struct drm_i915_private
*dev_priv, int val)
return mul;
/* CHV needs even values */
- return DIV_ROUND_CLOSEST(val * 2 * mul, czclk_freq) * 2;
+ return DIV_ROUND_CLOSEST(val * mul, czclk_freq) * 2;
}
int vlv_gpu_freq(struct drm_i915_private *dev_priv, int val)
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