[Intel-gfx] [PATCH v4 10/11] drm/i915: DVO pixel clock check

[Mika Kahola]

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 DVO.

V2:
- removed computation for max pixel clock

V3:
- cleanup by removing unnecessary lines

V4:
- clock check against max dotclock moved inside 'if (fixed_mode)'

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

diff --git a/drivers/gpu/drm/i915/intel_dvo.c b/drivers/gpu/drm/i915/intel_dvo.c
index dc532bb..924b724 100644
--- a/drivers/gpu/drm/i915/intel_dvo.c
+++ b/drivers/gpu/drm/i915/intel_dvo.c
@@ -201,6 +201,7 @@ intel_dvo_mode_valid(struct drm_connector *connector,
 		     struct drm_display_mode *mode)
 {
 	struct intel_dvo *intel_dvo = intel_attached_dvo(connector);
+	int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
 
 	if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
 		return MODE_NO_DBLESCAN;
@@ -212,6 +213,8 @@ intel_dvo_mode_valid(struct drm_connector *connector,
 			return MODE_PANEL;
 		if (mode->vdisplay > intel_dvo->panel_fixed_mode->vdisplay)
 			return MODE_PANEL;
+		if (mode->clock > max_dotclk)
+			return MODE_CLOCK_HIGH;
 	}
 
 	return intel_dvo->dev.dev_ops->mode_valid(&intel_dvo->dev, mode);
-- 
1.9.1