Re: [PATCH 0/2] tpm: Stop retrying TPMs that have stopped working

[Jarkko Sakkinen <jarkko@kernel.org>]

On Thu, Nov 12, 2026 at 03:57:29AM +0200, Jarkko Sakkinen wrote:
> On Thu, Nov 12, 2026 at 12:46:57AM +0200, Jarkko Sakkinen wrote:
> > On Thu, Nov 12, 2026 at 12:43:59AM +0200, Jarkko Sakkinen wrote:
> > > $ tpm2sh return-code 256
> > > TPM_RC_INITIALIZE
> > > 
> > > I.e. TPM has not been properly initialized by TPM2_Startup().
> > > 
> > > I.e. TPM is also saying that it is *disabled*.
> > > 
> > > So acting on this proven fact  makes most sense to me.
> > 
> > 
> > Actually, should we even disable TPM if it returns this error code
> > already at the level of tpm_transmit(). It is a guaranteed dead-end
> > to any possible TPM operation.
> > 
> > I.e. while this fixes hwrng issue I think it might be addressing the
> > issue at a wrong level.
> 
> I leave room for figuring out 1/2 but for the second issue I would just
> do what the attached patch does and call it a day.
> 
> Br, Jarkko

> From 093124e51a26de8191e21ce41988532ea7e0bc8a Mon Sep 17 00:00:00 2001
> From: Jarkko Sakkinen <jarkko@kernel.org>
> Date: Thu, 12 Nov 2026 03:55:00 +0200
> Subject: [PATCH] tpm: Disable TPM on TPM_RC_INITIALIZE
> 
> If the TPM has been spuriously disabled, the game is over. Let's reflect
> this truth with TPM_CHIP_FLAG_DISABLE.
> 
> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
> ---
>  drivers/char/tpm/tpm-interface.c | 5 +++++
>  drivers/char/tpm/tpm2-cmd.c      | 2 ++
>  2 files changed, 7 insertions(+)
> 
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 470b2da3234e..1f1e22341155 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -256,6 +256,11 @@ ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz)
>  		if (rc == TPM2_RC_TESTING && cc == TPM2_CC_SELF_TEST)
>  			break;
>  
> +		if (rc == TPM_RC_INITIALIZE) {
> +			chip->flag |= TPM_CHIP_FLAG_DISABLE;
> +			break;
> +		}
> +

Sorry, should be TPM2_RC_INITIALIZE. 

Br, Jarkko