drm/i915: SDVO pixel clock check

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 SDVO.

V2:
- removed computation for max pixel clock

V3:
- cleanup by removing unnecessary lines

V4:
- max_pixclk variable renamed as max_dotclk

Signed-off-by: Mika Kahola <mika.kahola@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1454419003-6001-5-git-send-email-mika.kahola@intel.com

diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index 2e1da060b0e1c6764886e6e0ccd23e09851f7c8e..4ecc076c40417c668e7ded7c7b51cfadac4104d7 100644 (file)
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -1527,6 +1527,7 @@ intel_sdvo_mode_valid(struct drm_connector *connector,
                      struct drm_display_mode *mode)
 {
        struct intel_sdvo *intel_sdvo = intel_attached_sdvo(connector);
+       int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
 
        if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
                return MODE_NO_DBLESCAN;
@@ -1537,6 +1538,9 @@ intel_sdvo_mode_valid(struct drm_connector *connector,
        if (intel_sdvo->pixel_clock_max < mode->clock)
                return MODE_CLOCK_HIGH;
 
+       if (mode->clock > max_dotclk)
+               return MODE_CLOCK_HIGH;
+
        if (intel_sdvo->is_lvds) {
                if (mode->hdisplay > intel_sdvo->sdvo_lvds_fixed_mode->hdisplay)
                        return MODE_PANEL;