Re: [PATCH 1/2] dt-bindings: drm/bridge: Add no-hpd property
From: Jayesh Choudhary
Date: Thu Mar 23 2023 - 08:27:16 EST
On 21/03/23 20:47, Krzysztof Kozlowski wrote:
On 21/03/2023 15:28, Jayesh Choudhary wrote:
On 21/03/23 18:08, Krzysztof Kozlowski wrote:
On 21/03/2023 13:02, Jayesh Choudhary wrote:
+ type: boolean
+ description:
+ Set if the HPD line on the bridge isn't hooked up to anything or is
+ otherwise unusable.
It's the property of the panel, not bridge. Unless you want to say that
bridge physically does not have HPD? Does it follow the standard in such
case?
MHDP does have hpd. But the mhdp driver should handle the cases when the
This is about bindings, not driver. Your driver can still handle this as
it wishes.
hpd pin of bridge is not connected to that of the DP-connector. This is
to add support for that. (optional property)
Which is indicated by panel no-hpd, right?
Actually no panel is involved in this. For TI SoC J721S2, the data
pipeline involves the bridge whose endpoint is directly the DP connector
with compatible 'dp-connector'. And in the binding dp-connector.yaml,
there isn't any 'no-hpd' property for this indication.
Does this clarifies the issue? Or did I misinterpret your comment?
Yes, then you only need to narrow which hardware does not have HPD
hooked up. Or at least clarify that it is not about driver having or not
having HPD control...
Okay. I will edit the commit message in v2. (after further review of the
driver changes for this series)
I will mention that the mhdp bridge can work without its HPD pin hooked
up to the connector, but the current bridge driver throws an error when
hpd line is not connected to the connector. For such cases, using this
optional property, we can bypass the hpd detection and instead use the
auxiliary channels connected to the DP connector to confirm the connection.
Thanks,
-Jayesh