[Intel-gfx] [PATCH v4 2/6] 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

V3:
- cleanup by removing unnecessary lines

V4:
- max_pixclk variable renamed as max_dotclk
- check for stereo mode added

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

diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index 8698a64..edb7e90 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -1202,11 +1202,19 @@ intel_hdmi_mode_valid(struct drm_connector *connector,
 	struct drm_device *dev = intel_hdmi_to_dev(hdmi);
 	enum drm_mode_status status;
 	int clock;
+	int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
 
 	if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
 		return MODE_NO_DBLESCAN;
 
 	clock = mode->clock;
+
+	if ((mode->flags & DRM_MODE_FLAG_3D_MASK) == DRM_MODE_FLAG_3D_FRAME_PACKING)
+		clock *= 2;
+
+	if (clock > max_dotclk)
+		return MODE_CLOCK_HIGH;
+
 	if (mode->flags & DRM_MODE_FLAG_DBLCLK)
 		clock *= 2;
 
-- 
1.9.1