patches.baytrail/0589-drm-i915-Add-comments-about-units-of-latency-values.patch

From e0f086d4869ed927b4eb22ac0bc4e385944e7cf7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Date: Thu, 1 Aug 2013 16:18:55 +0300
Subject: drm/i915: Add comments about units of latency values
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All the ILK+ WM compute functions take the latency values in 0.1us
units. Add a few comments to remind people about that.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
(cherry picked from commit 37126462a4feadeb3ff08c4b308a28e4db8c83a7)
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
---
 drivers/gpu/drm/i915/intel_pm.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 0254e620ba05..9b8c90ea81ff 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -2123,6 +2123,7 @@ static uint32_t ilk_pipe_pixel_rate(struct drm_device *dev,
 	return pixel_rate;
 }
 
+/* latency must be in 0.1us units. */
 static uint32_t ilk_wm_method1(uint32_t pixel_rate, uint8_t bytes_per_pixel,
 			       uint32_t latency)
 {
@@ -2137,6 +2138,7 @@ static uint32_t ilk_wm_method1(uint32_t pixel_rate, uint8_t bytes_per_pixel,
 	return ret;
 }
 
+/* latency must be in 0.1us units. */
 static uint32_t ilk_wm_method2(uint32_t pixel_rate, uint32_t pipe_htotal,
 			       uint32_t horiz_pixels, uint8_t bytes_per_pixel,
 			       uint32_t latency)
@@ -2200,7 +2202,10 @@ enum hsw_data_buf_partitioning {
 	HSW_DATA_BUF_PART_5_6,
 };
 
-/* For both WM_PIPE and WM_LP. */
+/*
+ * For both WM_PIPE and WM_LP.
+ * mem_value must be in 0.1us units.
+ */
 static uint32_t ilk_compute_pri_wm(struct hsw_pipe_wm_parameters *params,
 				   uint32_t mem_value,
 				   bool is_lp)
@@ -2227,7 +2232,10 @@ static uint32_t ilk_compute_pri_wm(struct hsw_pipe_wm_parameters *params,
 	return min(method1, method2);
 }
 
-/* For both WM_PIPE and WM_LP. */
+/*
+ * For both WM_PIPE and WM_LP.
+ * mem_value must be in 0.1us units.
+ */
 static uint32_t ilk_compute_spr_wm(struct hsw_pipe_wm_parameters *params,
 				   uint32_t mem_value)
 {
@@ -2247,7 +2255,10 @@ static uint32_t ilk_compute_spr_wm(struct hsw_pipe_wm_parameters *params,
 	return min(method1, method2);
 }
 
-/* For both WM_PIPE and WM_LP. */
+/*
+ * For both WM_PIPE and WM_LP.
+ * mem_value must be in 0.1us units.
+ */
 static uint32_t ilk_compute_cur_wm(struct hsw_pipe_wm_parameters *params,
 				   uint32_t mem_value)
 {
-- 
1.8.5.rc3