On Thu, Jul 31, 2014 at 03:08:29PM -0300, Paulo Zanoni wrote:
2014-06-27 20:04 GMT-03:00 ville.syrj...@linux.intel.com:
From: Ville Syrjälä ville.syrj...@linux.intel.com
The DDL registers can hold 7bit numbers. Make the most of those seven
bits by adjusting the threshold where we switch between the 64 vs. 32
precision multipliers.
Also we compute 'entries' to make the decision about precision, and then
we recompute the same value to calculate the actual drain latency. Just
use the already calculate 'entries' there.
Just an addition: don't we also want to WARN in case entires 64
(or in case the final result exceeds 7 bits, which is equivalent)?
Could be a separate patch too.
Yeah we could WARN when things go south. But there are some patches from
Gajanan pending that touch this code too, so probably best to wait until
those have gone in to avoid too much rebase pain.
With or without that: Reviewed-by: Paulo Zanoni paulo.r.zan...@intel.com
Signed-off-by: Ville Syrjälä ville.syrj...@linux.intel.com
---
drivers/gpu/drm/i915/intel_pm.c | 9 -
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_pm.c
b/drivers/gpu/drm/i915/intel_pm.c
index 9413184..3aa7959 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -1252,15 +1252,14 @@ static bool vlv_compute_drain_latency(struct
drm_device *dev,
pixel_size = crtc-primary-fb-bits_per_pixel / 8; /* BPP */
entries = (clock / 1000) * pixel_size;
- *plane_prec_mult = (entries 256) ?
+ *plane_prec_mult = (entries 128) ?
DRAIN_LATENCY_PRECISION_64 : DRAIN_LATENCY_PRECISION_32;
- *plane_dl = (64 * (*plane_prec_mult) * 4) / ((clock / 1000) *
-pixel_size);
+ *plane_dl = (64 * (*plane_prec_mult) * 4) / entries;
entries = (clock / 1000) * 4; /* BPP is always 4 for cursor */
- *cursor_prec_mult = (entries 256) ?
+ *cursor_prec_mult = (entries 128) ?
DRAIN_LATENCY_PRECISION_64 : DRAIN_LATENCY_PRECISION_32;
- *cursor_dl = (64 * (*cursor_prec_mult) * 4) / ((clock / 1000) * 4);
+ *cursor_dl = (64 * (*cursor_prec_mult) * 4) / entries;
return true;
}
--
1.8.5.5
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--
Paulo Zanoni
--
Ville Syrjälä
Intel OTC
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