Re: [regression] Since kernel 6.3.1 logitech unify receiver not working properly

On Thu, 25 May 2023, Jiri Kosina wrote:

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That bug is pre-existing (ie the problem was not introduced by that
commit), but who knows if the retry makes things worse (ie if it then
triggers on a retry, the response data will be the *previous* response).

The whole "goto exit" games should be removed too, because we're in a
for-loop, and instead of "goto exit" it should just do "break".

IOW, something like this might be worth testing.

That said, while I think the code is buggy, I doubt this is the actual
cause of the problem people are reporting. But it would be lovely to
hear if the attached patch makes any difference, and I think this is
fixing a real - but unlikely - problem anyway.

FWIW, Linus, your patch is
Reviewed-by: Benjamin Tissoires <redacted>

Feel free to submit it to us or to apply it directly if you prefer as
this is clearly a fix for a code path issue.

It would be nice to hear from the people who were able to reproduce the 
issue whether this makes any observable difference in behavior though. I 
don't currently think it would, as it fixes a potential NULL pointer 
dereference, which is not what has been reported.

Has anyone of the affected people tried to bisect the issue?

Could anyone who is able to reproduce the issue please check whether 
reverting

	586e8fede7953b16 ("HID: logitech-hidpp: Retry commands when device is busy")

has any observable effect?

Thanks,

-- 
Jiri Kosina
SUSE Labs