Re: TPM operation times out (very rarely)

[Jarkko Sakkinen <jarkko@kernel.org>]

On Fri, Feb 07, 2025 at 09:26:16AM +0000, Jonathan McDowell wrote:
> > The whole arithmetic with timeout_a/b/c is mostly gibberish and could
> > be replaced with a single "max" constant without issues (just set it
> > large enough).
> > 
> > They could be all be replaced with let's say 3s timeout in a constant.
> 
> This appears to have come up before:
> 
> https://lore.kernel.org/linux-integrity/358e89ed2b766d51b5f57abf31ab7a925ac63379.1552348123.git.calvinowens@fb.com/
> 
> That patch was deemed overly complex and it was suggested to split it
> up; I can't find any indication that was ever done which I guess is why
> the discussion died off.

Looking back I suggest splitting timeouts and durations into separate
patches:

https://lore.kernel.org/linux-integrity/20190312145553.GB6682@linux.intel.com/

> So just to clarify, this more recent patch is working around a situation
> where the status register gets stuck and needs a complete retry of the
> command send - it's an Infineon errata, not something that would be
> fixed with a longer timeout.

Hmm... please shout if I ignore something but if we could -ERESTARTSYS
semantics here that should ignite completely new transmit flow, wouldn't
it?

I'm not seeing this locally so far unfortunately.

BR, Jarkko