drm/i915: TV 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 TV.

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/1454419003-6001-7-git-send-email-mika.kahola@intel.com

diff --git a/drivers/gpu/drm/i915/intel_tv.c b/drivers/gpu/drm/i915/intel_tv.c
index 5034b0055169512ca816c507e69fa1ae7dd74a79..d21f75bda96e0aa173ff077d6335286845c556a3 100644 (file)
--- a/drivers/gpu/drm/i915/intel_tv.c
+++ b/drivers/gpu/drm/i915/intel_tv.c
@@ -897,6 +897,10 @@ intel_tv_mode_valid(struct drm_connector *connector,
 {
        struct intel_tv *intel_tv = intel_attached_tv(connector);
        const struct tv_mode *tv_mode = intel_tv_mode_find(intel_tv);
+       int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
+
+       if (mode->clock > max_dotclk)
+               return MODE_CLOCK_HIGH;
 
        /* Ensure TV refresh is close to desired refresh */
        if (tv_mode && abs(tv_mode->refresh - drm_mode_vrefresh(mode) * 1000)