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

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Message-ID: <Z-7YHkb_2Dpz7GpV@kernel.org>
Date: Thu, 3 Apr 2025 21:49:02 +0300
From: Jarkko Sakkinen <jarkko@...nel.org>
To: Michal Suchanek <msuchanek@...e.de>
Cc: Peter Huewe <peterhuewe@....de>, 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

On Thu, Apr 03, 2025 at 08:25:05PM +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.
> 
> Timeout C is retried since
> commit de9e33df7762 ("tpm, tpm_tis: Workaround failed command reception on Infineon devices")
> 
> Timeout B still needs to be extended.
> 
> Link: https://lore.kernel.org/linux-integrity/Z5pI07m0Muapyu9w@kitsune.suse.cz/
> Signed-off-by: Michal Suchanek <msuchanek@...e.de>
> ---
> V2: Only extend timeout B

git format-patch --v2 ;-)

NP, but use --v3 next time...

> ---
>  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 */

nit: secs (that said, don't care that much)

>  	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,
> -- 
> 2.47.1
> 

Have you tested with:

https://web.git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd.git/commit/?id=de9e33df7762abbfc2a1568291f2c3a3154c6a9d

?

BR, Jarkko