[Intel-gfx] [PATCH v2 03/11] drm/i915: HDMI 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 HDMI.

V2:
- removed computation for max dot clock

Signed-off-by: Mika Kahola <mika.kahola at intel.com>
---
 drivers/gpu/drm/i915/intel_hdmi.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index 70bad5b..b85efaa 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -1191,15 +1191,22 @@ intel_hdmi_mode_valid(struct drm_connector *connector,
 {
 	struct intel_hdmi *hdmi = intel_attached_hdmi(connector);
 	struct drm_device *dev = intel_hdmi_to_dev(hdmi);
+	struct drm_i915_private *dev_priv = to_i915(dev);
 	enum drm_mode_status status;
 	int clock;
+	int max_pixclk = dev_priv->max_dotclk;
 
 	if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
 		return MODE_NO_DBLESCAN;
 
 	clock = mode->clock;
-	if (mode->flags & DRM_MODE_FLAG_DBLCLK)
+	if (mode->flags & DRM_MODE_FLAG_DBLCLK) {
 		clock *= 2;
+		max_pixclk *= 2;
+	}
+
+	if (clock > max_pixclk)
+		return MODE_CLOCK_HIGH;
 
 	/* check if we can do 8bpc */
 	status = hdmi_port_clock_valid(hdmi, clock, true);
-- 
1.9.1