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

[Jonathan McDowell <noodles@earth.li>]

On Fri, Apr 04, 2025 at 11:10:12AM +0300, Jarkko Sakkinen wrote:
>On Fri, Apr 04, 2025 at 09:51:29AM +0200, Michal Suchánek wrote:
>> On Thu, Apr 03, 2025 at 09:43:19PM +0100, Jonathan McDowell wrote:
>> > On Thu, Apr 03, 2025 at 09:45:21PM +0300, Jarkko Sakkinen 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.
>> > > >
>> > > > (Also shouldn't timeout_c already end up as 750ms, as it's
>> > > > max(TIS_SHORT_TIMEOUT, TPM2_TIMEOUT_C), and TIS_SHORT_TIMEOUT is 750 vs 200
>> > > > for TPM2_TIMEOUT_C? That doesn't seem to be borne out by your logs, nor my
>> > > > results.)
>> > >
>> > > Just noticed that the commit did not end up having fixes etc. tags:
>> > >
>> > > https://web.git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd.git/commit/?id=de9e33df7762abbfc2a1568291f2c3a3154c6a9d
>> > >
>> > > Should we forward to stable?
>> >
>> > It's a TPM bug rather than a kernel issue, so I don't think there's a valid
>> > Fixes: for it, but it's certainly stable material in my mind.
>>
>> In the more general sense of Fixes: indicating where the fix is
>> applicable it would be any kernel that supports TPM2.
>
>I tried applying the patch on 6.1-stable:
>
>~/work/kernel.org/stable/linux tags/v6.1.132
>$ git am -3 ~/Downloads/infineon.patch
>Applying: tpm, tpm_tis: Workaround failed command reception on Infineon devices
>Using index info to reconstruct a base tree...
>M	drivers/char/tpm/tpm_tis_core.c
>M	drivers/char/tpm/tpm_tis_core.h
>M	include/linux/tpm.h
>Falling back to patching base and 3-way merge...
>Auto-merging include/linux/tpm.h
>Auto-merging drivers/char/tpm/tpm_tis_core.h
>Auto-merging drivers/char/tpm/tpm_tis_core.c
>
>If no counter-opinions, I'd add:
>
>stable@vger.kernel.org # v6.1+
>
>I based this on Bookworm kernel.

It looks like Sasha has already autoselected it for 6.1, 6.6, 6.12, 6.13 
+ 6.14.

J.

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