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

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Message-ID: <Z-7VtSv675dPIsTu@kernel.org>
Date: Thu, 3 Apr 2025 21:38:45 +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 timeouts B and C

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.
> 
> Link: https://lore.kernel.org/linux-integrity/Z5pI07m0Muapyu9w@kitsune.suse.cz/
> Signed-off-by: Michal Suchanek <msuchanek@...e.de>
> ---
> An alternative would be to add an entry to vendor_timeout_overrides but
> I do not know how to determine the chip IDs to put into this table.
> ---
>  drivers/char/tpm/tpm_tis_core.h | 4 ++--
>  1 file 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..1ff565be2175 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,	/* 2 sec */

/* 4 secs */

>  	TIS_TIMEOUT_MIN_ATML = 14700,	/* usecs */
>  	TIS_TIMEOUT_MAX_ATML = 15000,	/* usecs */
>  };
> @@ -64,7 +64,7 @@ enum tis_defaults {
>   */
>  #define TIS_TIMEOUT_A_MAX	max_t(int, TIS_SHORT_TIMEOUT, TPM2_TIMEOUT_A)
>  #define TIS_TIMEOUT_B_MAX	max_t(int, TIS_LONG_TIMEOUT, TPM2_TIMEOUT_B)
> -#define TIS_TIMEOUT_C_MAX	max_t(int, TIS_SHORT_TIMEOUT, TPM2_TIMEOUT_C)
> +#define TIS_TIMEOUT_C_MAX	max_t(int, TIS_LONG_TIMEOUT, TPM2_TIMEOUT_C)
>  #define TIS_TIMEOUT_D_MAX	max_t(int, TIS_SHORT_TIMEOUT, TPM2_TIMEOUT_D)
>  
>  #define	TPM_ACCESS(l)			(0x0000 | ((l) << 12))
> -- 
> 2.47.1
> 
> 

BR, Jarkko