Re: [PATCH 4/8] drm/bridge: dw-hdmi: document the output_port field

Damon Ding
2026-03-26T09:20:31Z

On 3/26/2026 3:25 PM, Liu Ying wrote:
> Hi Luca,
>
> On Fri, Mar 20, 2026 at 11:46:15AM +0100, Luca Ceresoli wrote:
>> The meaning of this flag may not be obvious at first sight.
>>
>> Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
>> ---
>> include/drm/bridge/dw_hdmi.h | 5 +++++
>> 1 file changed, 5 insertions(+)
>>

First of all, these changes related to the DW HDMI controller work well
when tested on RK3399 HDMI.

>> diff --git a/include/drm/bridge/dw_hdmi.h b/include/drm/bridge/dw_hdmi.h
>> index 336f062e1f9d..45f6ba1a8ee1 100644
>> --- a/include/drm/bridge/dw_hdmi.h
>> +++ b/include/drm/bridge/dw_hdmi.h
>> @@ -126,6 +126,11 @@ struct dw_hdmi_phy_ops {
>> struct dw_hdmi_plat_data {
>> struct regmap *regm;
>>
>> + /*
>> + * The HDMI output port number (which must be 1) if it is described
>
> I'd rephrase:
> The HDMI output port number must be 1 ...
>

Yes, the output port number should be 1, but I found that the output
port number in the Rockchip-side dw-hdmi driver remains 0.

Therefore, it may be better to adapt the dw-hdmi drivers across all
platforms to the bridge-connector architecture simultaneously.

This would allow removing &dw_hdmi_plat_data.output_port and unify the
setting of DRM_BRIDGE_ATTACH_NO_CONNECTOR during the attach stage.
(Just as the Analogix DP driver does [0])

[0]
https://lore.kernel.org/all/20260319071452.1961274-1-damon.ding@rock-chips.com/

>> + * in the device tree. 0 if the device tree does not describe the
>> + * next component (legacy mode).
>
> Maybe be a bit more specific about "legacy mode":
> legacy mode without DRM_BRIDGE_ATTACH_NO_CONNECTOR flag when attaching bridge
> ?
>
> Reviewed-by: Liu Ying <victor.liu@nxp.com>
>
>> + */
>> unsigned int output_port;
>>
>> unsigned long input_bus_encoding;
>>
>

Best regards,
Damon