[Intel-gfx] [PATCH] drm/i915/glk: CDCLK calculation changes for glk
Madhav Chauhan
madhav.chauhan at intel.com
Tue Feb 7 10:48:46 UTC 2017
As per BSPEC, valid cdclk values for glk are 79.2, 158.4, 316.8 Mhz.
Practically we can achive only 99% of these cdclk values. So cdclk
should be calculated for the given pixclk as per that otherwise it may
lead to screen corruption for some scenarios.
Signed-off-by: Madhav Chauhan <madhav.chauhan at intel.com>
---
drivers/gpu/drm/i915/intel_display.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 45e5874..2e1bfe9 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6544,9 +6544,9 @@ static int valleyview_calc_cdclk(struct drm_i915_private *dev_priv,
static int glk_calc_cdclk(int max_pixclk)
{
- if (max_pixclk > 2 * 158400)
+ if (max_pixclk > DIV_ROUND_UP(2 * 158400 * 99, 100))
return 316800;
- else if (max_pixclk > 2 * 79200)
+ else if (max_pixclk > DIV_ROUND_UP(2 * 79200 * 99, 100))
return 158400;
else
return 79200;
--
1.9.1
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