Re: [PATCH 0/9] platform/surface: aggregator: Improve target/source handling in SSH messages

From: Maximilian Luz
Date: Thu Dec 08 2022 - 11:19:09 EST


On 12/8/22 17:03, Hans de Goede wrote:
Hi Maximilian,

On 12/2/22 23:33, Maximilian Luz wrote:
We have some new insights into the Serial Hub protocol, obtained through
reverse engineering. In particular, regarding the command structure. The
input/output target IDs actually represent source and target IDs of
(what looks like) physical entities (specifically: host, SAM EC, KIP EC,
debug connector, and SurfLink connector).

This series aims to improve handling of messages with regards to those
new findings and, mainly, improve clarity of the documentation and usage
around those fields.

See the discussion in

https://github.com/linux-surface/surface-aggregator-module/issues/64

for more details.

There are a couple of standouts:

- Patch 1 ensures that we only handle commands actually intended for us.
It's possible that we receive messages not intended for us when we
enable debugging. I've kept it intentionally minimal to simplify
backporting. The rest of the series patch 9 focuses more on clarity
and documentation, which is probably too much to backport.

- Patch 8 touches on multiple subsystems. The intention is to enforce
proper usage and documentation of target IDs in the SSAM_SDEV() /
SSAM_VDEV() macros. As it directly touches those macros I
unfortunately can't split it up by subsystem.

- Patch 9 is a loosely connected cleanup for consistency.

Thank you for the patches. Unfortunately I don't have time atm to
review this.

And the next 2 weeks are the merge window, followed by 2 weeks
of christmas vacation.

So I'm afraid that I likely won't get around to reviewing
this until the week of January 9th.

Sure, no worries and no rush. Thanks for the heads-up.

Just as a note: While patch 1 is a "fix", I don't consider it
time-critical in any way. The underlying issue only appears if you
explicitly enable debug mode on the SAM EC. So no need to hurry.

Happy holidays.

Regards,
Max