[PATCH 13/13 v2] drm/i915/skl: Prefer even dividers for SKL DPLLs

From: Damien Lespiau <damien.lespiau@intel.com>
To: intel-gfx@lists.freedesktop.org
Subject: [PATCH 13/13 v2] drm/i915/skl: Prefer even dividers for SKL DPLLs
Date: Thu, 25 Jun 2015 16:19:24 +0100	[thread overview]
Message-ID: <1435245564-30754-1-git-send-email-damien.lespiau@intel.com> (raw)
In-Reply-To: <CA+gsUGTOtfq1rZ9VMcv7P7+N2n46J9z5TOPcFQKo2ekVqGMPBA@mail.gmail.com>

Currently, if an odd divider improves the deviation (minimizes it), we
take that divider. The recommendation is to prefer even dividers.

v2: Move the check at the right place after having inverted the two for
    loops in the previous patch.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
---
 drivers/gpu/drm/i915/intel_ddi.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index 6e964ef..f6b3ccc 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -1317,6 +1317,13 @@ skl_ddi_calculate_wrpll(int clock /* in Hz */,
 						      p);
 			}
 		}
+
+		/*
+		 * If a solution is found with an even divider, prefer
+		 * this one.
+		 */
+		if (d == 0 && ctx.p)
+			break;
 	}
 
 	if (!ctx.p) {
-- 
2.1.0

_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/intel-gfx
