Re: [PATCH v3 07/11] drm/i915: CRT pixel clock check

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Fri, Jul 31, 2015 at 03:13:56PM +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 CRT.
> 
> V2:
> - removed computation for max pixel clock
> 
> V3:
> - cleanup by removing unnecessary lines
> 
> Signed-off-by: Mika Kahola <mika.kahola@intel.com>

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

> ---
>  drivers/gpu/drm/i915/intel_crt.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
> index 5d78c1f..40ded5f 100644
> --- a/drivers/gpu/drm/i915/intel_crt.c
> +++ b/drivers/gpu/drm/i915/intel_crt.c
> @@ -290,6 +290,7 @@ intel_crt_mode_valid(struct drm_connector *connector,
>  		     struct drm_display_mode *mode)
>  {
>  	struct drm_device *dev = connector->dev;
> +	int max_pixclk = to_i915(dev)->max_dotclk;
>  
>  	int max_clock = 0;
>  	if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
> @@ -305,6 +306,9 @@ intel_crt_mode_valid(struct drm_connector *connector,
>  	if (mode->clock > max_clock)
>  		return MODE_CLOCK_HIGH;
>  
> +	if (mode->clock > max_pixclk)
> +		return MODE_CLOCK_HIGH;
> +
>  	/* The FDI receiver on LPT only supports 8bpc and only has 2 lanes. */
>  	if (HAS_PCH_LPT(dev) &&
>  	    (ironlake_get_lanes_required(mode->clock, 270000, 24) > 2))
> -- 
> 1.9.1
> 
> _______________________________________________
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> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Ville Syrjälä
Intel OTC
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