Re: [PATCH v5 2/4] drm/i915: LVDS pixel clock check

Ville Syrjälä
2015-08-21T10:57:39Z

On Tue, Aug 18, 2015 at 02:37:00PM +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 LVDS.
>
> V2:
> - removed computation for max pixel clock
>
> V3:
> - cleanup by removing unnecessary lines
>
> V4:
> - moved supported dotclock check from mode_valid() to intel_lvds_init()
>
> V5:
> - dotclock check moved back to mode_valid() function
> - dotclock check for fixed mode
>
> Signed-off-by: Mika Kahola <mika.kahola@intel.com>

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

> ---
> drivers/gpu/drm/i915/intel_lvds.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
> index 881b5d1..0794dc8 100644
> --- a/drivers/gpu/drm/i915/intel_lvds.c
> +++ b/drivers/gpu/drm/i915/intel_lvds.c
> @@ -289,11 +289,14 @@ intel_lvds_mode_valid(struct drm_connector *connector,
> {
> struct intel_connector *intel_connector = to_intel_connector(connector);
> struct drm_display_mode *fixed_mode = intel_connector->panel.fixed_mode;
> + int max_pixclk = to_i915(connector->dev)->max_dotclk_freq;
>
> if (mode->hdisplay > fixed_mode->hdisplay)
> return MODE_PANEL;
> if (mode->vdisplay > fixed_mode->vdisplay)
> return MODE_PANEL;
> + if (fixed_mode->clock > max_pixclk)
> + return MODE_CLOCK_HIGH;
>
> return MODE_OK;
> }
> --
> 1.9.1
>
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--
Ville Syrjälä
Intel OTC