Re: [PATCH] tpm: Make timeout logic simpler and more robust

Jarkko Sakkinen
2019-03-12T14:56:02Z

On Mon, Mar 11, 2019 at 04:54:04PM -0700, Calvin Owens wrote:
> We're having lots of problems with TPM commands timing out, and we're
> seeing these problems across lots of different hardware (both v1/v2).
>
> I instrumented the driver to collect latency data, but I wasn't able to
> find any specific timeout to fix: it seems like many of them are too
> aggressive. So I tried replacing all the timeout logic with a single
> universal long timeout, and found that makes our TPMs 100% reliable.
>
> Given that this timeout logic is very complex, problematic, and appears
> to serve no real purpose, I propose simply deleting all of it.
>
> Signed-off-by: Calvin Owens <calvinowens@fb.com>

In the current form the commit is doing way too much. I would like to
consider duration (command-response latency) and timeouts (state change
latency) separately.

/Jarkko