drm/i915: DisplayPort 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 DisplayPort.

V2:
- removed computation for max DOT clock

V3:
- cleanup by removing unnecessary lines

V4:
- max_pixclk 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/1454419003-6001-2-git-send-email-mika.kahola@intel.com
This commit is contained in:
Mika Kahola 2016-02-02 15:16:38 +02:00 committed by Daniel Vetter
parent ff3dc0875c
commit 799487f51d

View File

@ -203,6 +203,7 @@ intel_dp_mode_valid(struct drm_connector *connector,
struct drm_display_mode *fixed_mode = intel_connector->panel.fixed_mode;
int target_clock = mode->clock;
int max_rate, mode_rate, max_lanes, max_link_clock;
int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
if (is_edp(intel_dp) && fixed_mode) {
if (mode->hdisplay > fixed_mode->hdisplay)
@ -220,7 +221,7 @@ intel_dp_mode_valid(struct drm_connector *connector,
max_rate = intel_dp_max_data_rate(max_link_clock, max_lanes);
mode_rate = intel_dp_link_required(target_clock, 18);
if (mode_rate > max_rate)
if (mode_rate > max_rate || target_clock > max_dotclk)
return MODE_CLOCK_HIGH;
if (mode->clock < 10000)