Re: [tpmdd-devel] tpm_tis occasionally hangs on modprobe (multiple reports in Debian)

[Jurij S. <ju...@wo...>]

On Thu, Jan 05, 2012 at 06:44:05AM -0500, Stefan Berger wrote:
> On 01/05/2012 06:11 AM, Jurij Smakov wrote:
> >[Resending from a subscribed address, original message stuck in
> >moderation queue.]
> >
> >Hello,
> >
> >A number of users reported an occasional hang during boot due to stuck
> >modprobe process (invoked by udev) with 3.1.x kernels in Debian. Below
> >is the debugging information I've sent to Debian bug (obtained on my
> >Thinkpad X220), which can be viewed at
> >
> >http://bugs.debian.org/649033
> 
> Can you recompile the Debian kernel and apply the following patch?
> The problem is likely related to the particular TPM in the X220. Let
> me know if this patch improves things. Thanks.

Hi Stefan,

With this patch I was able to perform 500 tpm_tis.ko module 
insert/remove cycles without ever experiencing a hang. Without the 
patch it's sufficient to do 5-10 cycles before modprobe hangs on 
module insertion for a while. Thus, it looks like it is an 
improvement, so please push it upstream. Feel free to add:

Tested-by: Jurij Smakov <ju...@wo...>

Thanks.

>   Stefan
> 
> 
> Signed-off-by: Stefan Berger<st...@li...>
> 
> ---
>   drivers/char/tpm/tpm_tis.c |    3 +++
>   1 file changed, 3 insertions(+)
> 
> Index: linux-2.6/drivers/char/tpm/tpm_tis.c
> ===================================================================
> --- linux-2.6.orig/drivers/char/tpm/tpm_tis.c
> +++ linux-2.6/drivers/char/tpm/tpm_tis.c
> @@ -432,6 +432,9 @@ static int probe_itpm(struct tpm_chip *c
>   out:
>       itpm = rem_itpm;
>       tpm_tis_ready(chip);
> +    /* some TPMs need a break here otherwise they will not work
> +     * correctly on the immediately subsequent command */
> +    msleep(chip->vendor.timeout_b);
>       release_locality(chip, chip->vendor.locality, 0);
> 
>       return rc;
> 
> 
> 

-- 
Jurij Smakov                                           ju...@wo...
Key: http://www.wooyd.org/pgpkey/                      KeyID: C99E03CC