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[v3,02/11] drm/i915: DisplayPort pixel clock check

Message ID 1438344840-3490-3-git-send-email-mika.kahola@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Mika Kahola July 31, 2015, 12:13 p.m. UTC
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

Signed-off-by: Mika Kahola <mika.kahola@intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Ville Syrjälä Aug. 12, 2015, 6:50 p.m. UTC | #1
On Fri, Jul 31, 2015 at 03:13:51PM +0300, Mika Kahola wrote:
> 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
> 
> Signed-off-by: Mika Kahola <mika.kahola@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_dp.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 44f8a32..5faeadb 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -206,6 +206,7 @@ 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_pixclk = to_i915(connector->dev)->max_dotclk;
>  
>  	if (is_edp(intel_dp) && fixed_mode) {
>  		if (mode->hdisplay > fixed_mode->hdisplay)
> @@ -223,7 +224,7 @@ 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_pixclk)
>  		return MODE_CLOCK_HIGH;

This one ends up checking the fixed_mode clock every time, but I think I
already declared that to OK, so let's go with it.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>


>  	if (mode->clock < 10000)
> -- 
> 1.9.1
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 44f8a32..5faeadb 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -206,6 +206,7 @@  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_pixclk = to_i915(connector->dev)->max_dotclk;
 
 	if (is_edp(intel_dp) && fixed_mode) {
 		if (mode->hdisplay > fixed_mode->hdisplay)
@@ -223,7 +224,7 @@  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_pixclk)
 		return MODE_CLOCK_HIGH;
 
 	if (mode->clock < 10000)