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
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index a073f04..65d5084 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -203,6 +203,7 @@
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 @@
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)