[Intel-gfx] [PATCH] drm/i915/glk: CDCLK calculation changes for glk

[Madhav Chauhan]

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(HW team
checking on this). So cdclk should be calculated for the given pixclk as
per that otherwise it may lead to screen corruption for some scenarios.

v2: Rebased to new CDLCK code framework

Signed-off-by: Madhav Chauhan <madhav.chauhan at intel.com>
---
 drivers/gpu/drm/i915/intel_cdclk.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_cdclk.c b/drivers/gpu/drm/i915/intel_cdclk.c
index d643c0c..834df68 100644
--- a/drivers/gpu/drm/i915/intel_cdclk.c
+++ b/drivers/gpu/drm/i915/intel_cdclk.c
@@ -1071,9 +1071,9 @@ static int bxt_calc_cdclk(int max_pixclk)
 
 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