[Intel-gfx] [PATCH] drm/i915: Allow user modes to exceed DVI 165MHz limit

[Jani Nikula]

Pushed to -fixes, thanks for the patch and Daniel's r-b on IRC.

BR,
Jani.

On Thu, 27 Mar 2014, ville.syrjala at linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> In commit
>  commit 6375b768a9850b6154478993e5fb566fa4614a9c
>  Author: Ville Syrjälä <ville.syrjala at linux.intel.com>
>  Date:   Mon Mar 3 11:33:36 2014 +0200
>
>     drm/i915: Reject >165MHz modes w/ DVI monitors
>
> the driver started to filter out display modes which exceed the
> single-link DVI 165Mz dotclock limits when the monitor doesn't report
> itself as being HDMI compliant. The intent was to filter out all
> EDID derived modes that require dual-link DVI to operate since we
> don't support dual-link.
>
> However the patch went a bit too far and also causes the driver to reject
> such modes even when specified by the user. Normally we don't check the
> sink limitations when setting a mode from the user. This allows the user
> to specify any mode whether the sink reports to support it or not. This
> can be useful since often the sinks support more modes than they report
> in the EDID.
>
> So relax the checks a bit, and apply the single-link DVI dotclock limit
> only when filtering the mode list, and ignore the limit when setting
> a user specified mode.
>
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=72961
> Tested-by: Nicholas Vinson <nvinson at comcast.net>
> Cc: stable at vger.kernel.org
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_hdmi.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> index ee3181e..ca5d23d 100644
> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> @@ -841,11 +841,11 @@ static void intel_disable_hdmi(struct intel_encoder *encoder)
>  	}
>  }
>  
> -static int hdmi_portclock_limit(struct intel_hdmi *hdmi)
> +static int hdmi_portclock_limit(struct intel_hdmi *hdmi, bool respect_dvi_limit)
>  {
>  	struct drm_device *dev = intel_hdmi_to_dev(hdmi);
>  
> -	if (!hdmi->has_hdmi_sink || IS_G4X(dev))
> +	if ((respect_dvi_limit && !hdmi->has_hdmi_sink) || IS_G4X(dev))
>  		return 165000;
>  	else if (IS_HASWELL(dev) || INTEL_INFO(dev)->gen >= 8)
>  		return 300000;
> @@ -857,7 +857,8 @@ static enum drm_mode_status
>  intel_hdmi_mode_valid(struct drm_connector *connector,
>  		      struct drm_display_mode *mode)
>  {
> -	if (mode->clock > hdmi_portclock_limit(intel_attached_hdmi(connector)))
> +	if (mode->clock > hdmi_portclock_limit(intel_attached_hdmi(connector),
> +					       true))
>  		return MODE_CLOCK_HIGH;
>  	if (mode->clock < 20000)
>  		return MODE_CLOCK_LOW;
> @@ -875,7 +876,7 @@ bool intel_hdmi_compute_config(struct intel_encoder *encoder,
>  	struct drm_device *dev = encoder->base.dev;
>  	struct drm_display_mode *adjusted_mode = &pipe_config->adjusted_mode;
>  	int clock_12bpc = pipe_config->adjusted_mode.crtc_clock * 3 / 2;
> -	int portclock_limit = hdmi_portclock_limit(intel_hdmi);
> +	int portclock_limit = hdmi_portclock_limit(intel_hdmi, false);
>  	int desired_bpp;
>  
>  	if (intel_hdmi->color_range_auto) {
> -- 
> 1.8.3.2
>
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-- 
Jani Nikula, Intel Open Source Technology Center