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From: Madhav Chauhan <madhav.chauhan@intel.com>
To: intel-gfx@lists.freedesktop.org
Cc: ander.conselvan.de.oliveira@intel.com, jani.nikula@intel.com
Subject: [PATCH] drm/i915/glk: CDCLK calculation changes for glk
Date: Tue,  7 Feb 2017 05:48:46 -0500	[thread overview]
Message-ID: <1486464526-19132-1-git-send-email-madhav.chauhan@intel.com> (raw)

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@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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             reply	other threads:[~2017-02-07 10:48 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-07 10:48 Madhav Chauhan [this message]
2017-02-07 11:22 ` ✓ Fi.CI.BAT: success for drm/i915/glk: CDCLK calculation changes for glk Patchwork
2017-02-07 11:24 ` [PATCH] " Ville Syrjälä
2017-02-07 11:45   ` Jani Nikula
2017-02-16  7:21 Madhav Chauhan
2017-02-16 15:33 ` Jani Nikula
2017-03-16 10:31   ` Chauhan, Madhav
2017-03-16 13:10     ` Jani Nikula
2017-03-16 13:23       ` Ander Conselvan De Oliveira
2017-03-16 13:30         ` Jani Nikula
2017-03-17 13:40           ` Chauhan, Madhav
2017-03-20  8:00             ` Chauhan, Madhav
2017-03-20 18:03 Madhav Chauhan

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