On Mon, Mar 10, 2025 at 12:22:08PM +0000, Jonathan McDowell wrote:
> The change to only use interrupts to handle supported status changes
> introduced an issue when it is necessary to poll for the status. Rather
> than checking for the status after sleeping the code now sleeps after
> the check. This means a correct, but slower, status change on the part
> of the TPM can be missed, resulting in a spurious timeout error,
> especially on a more loaded system. Switch back to sleeping *then*
> checking. An up front check of the status has been done at the start of
> the function, so this does not cause an additional delay when the status
> is already what we're looking for.
>
> Cc: stable@xxxxxxxxxxxxxxx # v6.4+
> Fixes: e87fcf0dc2b4 ("tpm, tpm_tis: Only handle supported interrupts")
> Signed-off-by: Jonathan McDowell <noodles@xxxxxxxx>
> Reviewed-by: Michal Suchánek <msuchanek@xxxxxxx>
> Reviewed-by: Lino Sanfilippo <l.sanfilippo@xxxxxxxxxx>
> ---
> v2: Reword commit message
> Don't needlessly wrap line
>
> drivers/char/tpm/tpm_tis_core.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index fdef214b9f6b..c969a1793184 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -114,11 +114,10 @@ static int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask,
> return 0;
> /* process status changes without irq support */
> do {
> + usleep_range(priv->timeout_min, priv->timeout_max);
> status = chip->ops->status(chip);
> if ((status & mask) == mask)
> return 0;
> - usleep_range(priv->timeout_min,
> - priv->timeout_max);
> } while (time_before(jiffies, stop));
> return -ETIME;
> }
> --
> 2.48.1
>
Probably apply late this and timeout fix late this week.
Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
BR, Jarkko
