Re: [PATCH v8 04/39] drm/connector: Add HDMI 2.0 scrambler infrastructure

[Maxime Ripard <mripard@kernel.org>]

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On Fri, Jul 03, 2026 at 11:54:33PM +0300, Cristian Ciocaltea wrote:
>> >> -	if (caps->supported_hdmi_ver >= HDMI_VERSION_2_0)
> >> +	if (caps->supported_hdmi_ver >= HDMI_VERSION_2_0) {
> >> +		if (!hdmi_funcs->scrambler_enable ||
> >> +		    !hdmi_funcs->scrambler_disable)
> >> +			return -EINVAL;
> >> +
> >> +		connector->hdmi.scrambler_supported = true;
> >>  		connector->hdmi.max_tmds_char_rate = HDMI_2_0_TMDS_CHAR_RATE_MAX_HZ;
> >> -	else if (caps->supported_hdmi_ver >= HDMI_VERSION_1_3)
> >> +	} else if (caps->supported_hdmi_ver >= HDMI_VERSION_1_3) {
> >>  		connector->hdmi.max_tmds_char_rate = HDMI_1_3_TMDS_CHAR_RATE_MAX_HZ;
> >> -	else if (caps->supported_hdmi_ver >= HDMI_VERSION_1_0)
> >> +	} else if (caps->supported_hdmi_ver >= HDMI_VERSION_1_0) {
> >>  		connector->hdmi.max_tmds_char_rate = HDMI_1_0_TMDS_CHAR_RATE_MAX_HZ;
> >> +	}
> >>  
> >>  	if (caps->max_tmds_char_rate) {
> >>  		if (caps->max_tmds_char_rate > connector->hdmi.max_tmds_char_rate)
> >> +
> >> +	/** @scdc_cb: Callback to be invoked as part of @scdc_work.
> >> +	 *
> >> +	 * Currently used to monitor sink-side scrambling status and retry
> >> +	 * setup if the sink resets it.
> >> +	 *
> >> +	 * This is assigned by the framework when making use of
> >> +	 * drm_connector_hdmi_enable_scrambling() helper.
> > 
> > No such helper. 
> 
> Right, I'll drop the reference to the helper name, as that's added later in the
> series.
> 
> > Also, please explain in the commit message, why do we
> > need to keep it configurable. Why the default is not enough?
> 
> We will need a separate callback to support HDMI 2.1, i.e. for link training
> management.  I’ll update the commit message accordingly.

I think I'm equally confused as Dmitry here. If scdc_cb is only called
if we're sending scrambled pixels but the monitor doesn't acknowledge it
initially, then the only thing we need to do is "if the scrambler's
enabled, call drm_scdc_set_scrambling()", then we don't need to set a
callback. And even if we ever need to deal with HDMI link training, then
we can still have the same function but with a couple of branches more.

Maxime

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