Re: [PATCH] tpm: tis: Increase the default for timeouts B and C

[Jonathan McDowell]

On Thu, Apr 03, 2025 at 01:56:37PM +0200, Michal Suchánek wrote:
> On Thu, Apr 03, 2025 at 12:00:36PM +0100, Jonathan McDowell wrote:
> > On Wed, Apr 02, 2025 at 10:07:39PM +0200, Michal Suchánek wrote:
> > > On Wed, Apr 02, 2025 at 06:45:40PM +0100, Jonathan McDowell wrote:
> > > > On Wed, Apr 02, 2025 at 07:21:30PM +0200, Michal Suchanek wrote:
> > > > > With some Infineon chips the timeouts in tpm_tis_send_data (both B and
> > > > > C) can reach up to about 2250 ms.
> > > > >
> > > > > Extend the timeout duration to accommodate this.
> > > >
> > > > The problem here is the bump of timeout_c is going to interact poorly with
> > > > the Infineon errata workaround, as now we'll wait 4s instead of 200ms to
> > > > detect the stuck status change.
> > >
> > > Yes, that's problematic. Is it possible to detect the errata by anything
> > > other than waiting for the timeout to expire?
> >
> > Not that I'm aware of, nor have seen in my experimentation. It's a "stuck"
> > status, so the timeout is how it's detected.
> >
> > OOI, have you tried back porting the fixes that are in mainline for 6.15 to
> > your frankenkernel? I _think_ the errata fix might end up resolving at least
> > the timeout for valid for you, as a side effect? We're currently rolling
> > them out across our fleet, but I don't have enough runtime yet to be sure
> > they've sorted all the timeout instances we see.
>
> When was that merged?

It hit Linus' tree last Friday I believe.

> The change I see is that sometimes EAGAIN is returned instead of ETIME
> but based on the previous discussion this is unlikely to help.

That sounds like you might have picked up the version with the typo that 
I posted to the list; it got fixed up before making it to mainline. The 
two patches I've backported locally are in mainline as:

7146dffa875cd00e7a7f918e1fce79c7593ac1fa tpm, tpm_tis: Fix timeout handling when waiting for TPM status
de9e33df7762abbfc2a1568291f2c3a3154c6a9d tpm, tpm_tis: Workaround failed command reception on Infineon devices

J.

--
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