Re: [PATCH v4 10/11] drm/i915: DVO pixel clock check

From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Mika Kahola <mika.kahola@intel.com>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH v4 10/11] drm/i915: DVO pixel clock check
Date: Fri, 14 Aug 2015 16:10:27 +0300	[thread overview]
Message-ID: <20150814131027.GA5176@intel.com> (raw)
In-Reply-To: <1439546611-3191-11-git-send-email-mika.kahola@intel.com>

On Fri, Aug 14, 2015 at 01:03:30PM +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 DVO.
> 
> V2:
> - removed computation for max pixel clock
> 
> V3:
> - cleanup by removing unnecessary lines
> 
> V4:
> - clock check against max dotclock moved inside 'if (fixed_mode)'
> 
> Signed-off-by: Mika Kahola <mika.kahola@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_dvo.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dvo.c b/drivers/gpu/drm/i915/intel_dvo.c
> index dc532bb..924b724 100644
> --- a/drivers/gpu/drm/i915/intel_dvo.c
> +++ b/drivers/gpu/drm/i915/intel_dvo.c
> @@ -201,6 +201,7 @@ intel_dvo_mode_valid(struct drm_connector *connector,
>  		     struct drm_display_mode *mode)
>  {
>  	struct intel_dvo *intel_dvo = intel_attached_dvo(connector);
> +	int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
>  
>  	if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
>  		return MODE_NO_DBLESCAN;
> @@ -212,6 +213,8 @@ intel_dvo_mode_valid(struct drm_connector *connector,
>  			return MODE_PANEL;
>  		if (mode->vdisplay > intel_dvo->panel_fixed_mode->vdisplay)
>  			return MODE_PANEL;
> +		if (mode->clock > max_dotclk)
> +			return MODE_CLOCK_HIGH;
>  	}

What we want here is duplicate the intel_dp.c logic exactly, ie. check
against fixed_mode->clock when it's around, otherwise check against
mode->clock.

>  
>  	return intel_dvo->dev.dev_ops->mode_valid(&intel_dvo->dev, mode);
> -- 
> 1.9.1
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Ville Syrjälä
Intel OTC
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