On 7/15/26 11:55 AM, Maxime Ripard wrote:
> On Mon, Jul 13, 2026 at 01:23:00PM +0300, Cristian Ciocaltea wrote:
>> On 7/13/26 11:50 AM, Maxime Ripard wrote:
>>> On Thu, Jul 09, 2026 at 10:25:54PM +0300, Cristian Ciocaltea wrote:
>>>> On 7/3/26 11:54 PM, Cristian Ciocaltea wrote:
>>>>> On 7/3/26 5:34 PM, Dmitry Baryshkov wrote:
>>>>>> On Thu, Jul 02, 2026 at 05:46:17PM +0300, Cristian Ciocaltea wrote:
>>>>>>> Add the connector-level infrastructure to support HDMI 2.0 scrambling:
>>>>>>>
>>>>>>> - A scrambler_supported flag to indicate whether the source supports the
>>>>>>> scrambling capability, in which case the newly introduced
>>>>>>> .scrambler_{enable|disable}() callbacks in drm_connector_hdmi_funcs
>>>>>>> are mandatory
>>>>>>
>>>>>> Do we need a flag? What would it mean if the flag is set, but the
>>>>>> callbacks are not? Can we drop the flag and use the presence of the
>>>>>> callbacks as a way to identify that scrambler is enabled?
>>>>>
>>>>> The flag is intended to be set only within
>>>>> drmm_connector_hdmi_init_with_caps()
>>>>> when drivers advertise HDMI 2.x capability, in which case it also ensures
>>>>> the
>>>>> callbacks are provided.
>>>>>
>>>>> We could drop the flag and instead have the init helper clear the
>>>>> callbacks if
>>>>> they were provided for HDMI 1.x. This might slightly reduce code
>>>>> readability,
>>>>> as it relies on checking the presence of individual callbacks -
>>>>> especially since
>>>>> we plan to extend this further with HDMI 2.1 support, providing four or
>>>>> five
>>>>> additional FRL-specific callbacks.
>>>>
>>>> I tried to replace the flag with a helper that checks the presence of (one
>>>> of)
>>>> the callbacks, but it's not straightforward to unset those for non-HDMI 2.x
>>>> cases since the hdmi_funcs argument is immutable.
>>>
>>> I'm not sure why we would need to unset them. If the driver states that
>>> it support HDMI 2.0, then it needs to be there, if it doesn't, then who
>>> cares? it's not going to be used. We can log a warning that it's
>>> inconsistent I guess, but there's no need to actively remove it.
>>
>> I was trying to address the use case where drivers provide the scrambler
>> callbacks despite not supporting HDMI 2.0.
>
> Scrambling got introduced with HDMI 2.0. That doesn't make sense, but
> it's not a total deal breaker, it's just going to be here unused. Hence
> why I was suggesting to put a warning there if you wanted to.
>
>> If we replace the scrambler_supported flag with a helper checking the
>> presence of the scrambler callbacks, then we would need to ensure the
>> callbacks do not exist in this case.
>
> Keep it simple:
>
> if (hdmi_version >= HDMI_VERSION_2_0)
> if (funcs->scrambler_enable)
> hdmi->scramblers_supported = true
> else
> return -EINVAL
> else
> drm_warn(warn, "Inconsistent HDMI version");
>
> We don't need anything more than that.
I dropped the scrambler_supported flag and introduced a helper:
static inline bool
drm_connector_hdmi_scrambler_supported(struct drm_connector *connector)
{
return connector->hdmi.funcs && connector->hdmi.funcs->scrambler_enable;
}
Therefore we need to ensure the callbacks are not set in the HDMI 1.x cases:
int drmm_connector_hdmi_init_with_caps()
{
...
if (caps->supported_hdmi_ver >= HDMI_VERSION_2_0) {
if (!hdmi_funcs->scrambler_enable ||
!hdmi_funcs->scrambler_disable)
return -EINVAL;
connector->hdmi.max_tmds_char_rate =
HDMI_2_0_TMDS_CHAR_RATE_MAX_HZ;
} else {
/*
* Scrambler callbacks are only valid for connectors advertising
* HDMI 2.0 capability. drm_connector_hdmi_scrambler_supported()
* relies on their presence to report scrambling support.
*/
if (hdmi_funcs->scrambler_enable ||
hdmi_funcs->scrambler_disable)
return -EINVAL;
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) {
connector->hdmi.max_tmds_char_rate =
HDMI_1_0_TMDS_CHAR_RATE_MAX_HZ;
}
}
...
}
