linux-kernel - Re: [PATCH] tpm: tis: Increase the default for timeout B

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Message-ID: <4e4640bd-0313-4594-9667-82340ed9368a@molgen.mpg.de>
Date: Thu, 3 Apr 2025 20:28:56 +0200
From: Paul Menzel <pmenzel@...gen.mpg.de>
To: Michal Suchanek <msuchanek@...e.de>
Cc: Peter Huewe <peterhuewe@....de>, Jarkko Sakkinen <jarkko@...nel.org>,
 Jason Gunthorpe <jgg@...pe.ca>, linux-integrity@...r.kernel.org,
 linux-kernel@...r.kernel.org, Jonathan McDowell <noodles@...th.li>
Subject: Re: [PATCH] tpm: tis: Increase the default for timeout B

Dear Michal,


Thank you for the patch. For the summary/title you could be more 
specific by using *Double*:

tpm: tis: Double default for timeout B to 4 s

Am 03.04.25 um 20:25 schrieb Michal Suchanek:
> With some Infineon chips the timeouts in tpm_tis_send_data (both B and
> C) can reach up to about 2250 ms.
> 
> Timeout C is retried since
> commit de9e33df7762 ("tpm, tpm_tis: Workaround failed command reception on Infineon devices")
> 
> Timeout B still needs to be extended.

It’d be great if you could amend the commit message and add the Infinion 
device you have problems with, and maybe also add the error behavior.

> Link: https://lore.kernel.org/linux-integrity/Z5pI07m0Muapyu9w@kitsune.suse.cz/
> Signed-off-by: Michal Suchanek <msuchanek@...e.de>
> ---
> V2: Only extend timeout B
> ---
>   drivers/char/tpm/tpm_tis_core.h | 2 +-
>   include/linux/tpm.h             | 2 +-
>   2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h
> index 970d02c337c7..c272c25eb9d4 100644
> --- a/drivers/char/tpm/tpm_tis_core.h
> +++ b/drivers/char/tpm/tpm_tis_core.h
> @@ -54,7 +54,7 @@ enum tis_int_flags {
>   enum tis_defaults {
>   	TIS_MEM_LEN = 0x5000,
>   	TIS_SHORT_TIMEOUT = 750,	/* ms */
> -	TIS_LONG_TIMEOUT = 2000,	/* 2 sec */
> +	TIS_LONG_TIMEOUT = 4000,	/* 4 sec */
>   	TIS_TIMEOUT_MIN_ATML = 14700,	/* usecs */
>   	TIS_TIMEOUT_MAX_ATML = 15000,	/* usecs */
>   };
> diff --git a/include/linux/tpm.h b/include/linux/tpm.h
> index 6c3125300c00..3db0b6a87d45 100644
> --- a/include/linux/tpm.h
> +++ b/include/linux/tpm.h
> @@ -224,7 +224,7 @@ enum tpm2_const {
>   
>   enum tpm2_timeouts {
>   	TPM2_TIMEOUT_A          =    750,
> -	TPM2_TIMEOUT_B          =   2000,
> +	TPM2_TIMEOUT_B          =   4000,
>   	TPM2_TIMEOUT_C          =    200,
>   	TPM2_TIMEOUT_D          =     30,
>   	TPM2_DURATION_SHORT     =     20,


Kind regards,

Paul