Re: [PATCH v3 16/17] platform/chrome: cros_ec_typec: Support DP muxing

On Fri, Aug 23, 2024 at 01:44:41PM -0700, Stephen Boyd wrote:

Quoting Tzung-Bi Shih (2024-08-22 07:37:05)

quoted

On Mon, Aug 19, 2024 at 03:38:30PM -0700, Stephen Boyd wrote:

...

quoted

quoted

+     /*
+      * Assume the first port to have HPD asserted is the one muxed to DP
+      * (i.e. active_port). When there's only one port this delays setting
+      * the active_port until HPD is asserted, but before that the
+      * drm_connector looks disconnected so active_port doesn't need to be
+      * set.
+      */
+     if (dp_bridge && hpd_asserted && !dp_bridge->active_port)
+             dp_bridge->active_port = port;
+
+     is_active_port = !dp_bridge || dp_bridge->active_port == port;

Why `!dp_bridge`?  When will `dp_bridge` be NULL?

I'll add a comment.

'dp_bridge' is NULL when this driver is running on non-DT platforms,
i.e. ACPI, or there isn't a graph/ports node for this device. The latter
could happen if there's some AP controlled piece of hardware that is a
typec switch, connected directly to a usb-c-connector. This is the case
on Kukui where we send the DP lanes directly to the usb-c-connector.

Thanks!

-- 
With Best Regards,
Andy Shevchenko