On 09/05/2023 12:30, Aradhya Bhatia wrote:
Hi all,
I have picked up this long standing series from Nikhil Devshatwar[1].
This series moves the tidss to using new connectoe model, where the SoC
driver (tidss) creates the connector and all the bridges are attached
with the flag DRM_BRIDGE_ATTACH_NO_CONNECTOR. It also now creates bridge
to support format negotiation and and 'simple' encoder to expose it to
the userspace.
Since the bridges do not create the connector, the bus_format and
bus_flag is set via atomic hooks.
Support format negotiations in the tfp410, sii902x and mhdp-8546 bridge
drivers as a first step before moving the connector model.
These patches were tested on AM625-SK EVM, AM625 SoC based BeaglePlay,
and J721E-SK. Display support for AM625 SoC has not been added upstream
and is a WIP. To test this series on AM625 based platforms, basic
display support patches, (for driver + devicetree), can be found in
the "next_AttachNoConn" branch on my github fork[2].
Not exactly related to this series, but I was testing this with J7 EVM
and a Dell DP monitor.
I'm seeing DPCD errors quite often, which also sometimes cause link
training errors. E.g.:
cdns-mhdp8546 a000000.dp-bridge: Failed to read DPCD addr 0
cdns-mhdp8546 a000000.dp-bridge: Failed to adjust Link Training.
I tested retrying the read/write when it fails, and that seemed to help
a bit, but not always. Are you using the firmware that's on the upstream
linux-firmware repo?
Tomi
