[PATCH v3 02/11] drm/i915: DisplayPort pixel clock check

From: Mika Kahola <mika.kahola@intel.com>
To: intel-gfx@lists.freedesktop.org
Subject: [PATCH v3 02/11] drm/i915: DisplayPort pixel clock check
Date: Fri, 31 Jul 2015 15:13:51 +0300	[thread overview]
Message-ID: <1438344840-3490-3-git-send-email-mika.kahola@intel.com> (raw)
In-Reply-To: <1438344840-3490-1-git-send-email-mika.kahola@intel.com>

It is possible the we request to have a mode that has
higher pixel clock than our HW can support. This patch
checks if requested pixel clock is lower than the one
supported by the HW. The requested mode is discarded
if we cannot support the requested pixel clock.

This patch applies to DisplayPort.

V2:
- removed computation for max DOT clock

V3:
- cleanup by removing unnecessary lines

Signed-off-by: Mika Kahola <mika.kahola@intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 44f8a32..5faeadb 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -206,6 +206,7 @@ intel_dp_mode_valid(struct drm_connector *connector,
 	struct drm_display_mode *fixed_mode = intel_connector->panel.fixed_mode;
 	int target_clock = mode->clock;
 	int max_rate, mode_rate, max_lanes, max_link_clock;
+	int max_pixclk = to_i915(connector->dev)->max_dotclk;
 
 	if (is_edp(intel_dp) && fixed_mode) {
 		if (mode->hdisplay > fixed_mode->hdisplay)
@@ -223,7 +224,7 @@ intel_dp_mode_valid(struct drm_connector *connector,
 	max_rate = intel_dp_max_data_rate(max_link_clock, max_lanes);
 	mode_rate = intel_dp_link_required(target_clock, 18);
 
-	if (mode_rate > max_rate)
+	if (mode_rate > max_rate || target_clock > max_pixclk)
 		return MODE_CLOCK_HIGH;
 
 	if (mode->clock < 10000)
-- 
1.9.1

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