On Wed, Sep 24, 2014 at 11:59:40AM -0600, Jason Gunthorpe wrote:
> On Wed, Sep 24, 2014 at 01:34:11PM -0400, Stefan Berger wrote:
> > On 09/24/2014 01:13 PM, Jason Gunthorpe wrote:
> > >On Wed, Sep 24, 2014 at 12:06:02PM +0300, Jarkko Sakkinen wrote:
> > >>+static ssize_t durations_show(struct device *dev, struct
> > >>device_attribute *attr,
> > >>+ char *buf)
> > >>+{
> > >>+ struct tpm_chip *chip = dev_get_drvdata(dev);
> > >>+
> > >>+ if (chip->vendor.duration[TPM_LONG] == 0)
> > >>+ return 0;
> > >>+
> > >>+ return sprintf(buf, "%d %d %d [%s]\n",
> > >>+ jiffies_to_usecs(chip->vendor.duration[TPM_SHORT]),
> > >>+ jiffies_to_usecs(chip->vendor.duration[TPM_MEDIUM]),
> > >>+ jiffies_to_usecs(chip->vendor.duration[TPM_LONG]),
> > >>+ chip->vendor.duration_adjusted
> > >>+ ? "adjusted" : "original");
> > >>+}
> > >>+static DEVICE_ATTR_RO(durations);
> > >Seem useless since the durations are constant, drop it?
> >
> > We show them for TPM 1.2 as well, so I'd keep them fo TPM2.
>
> The durations are constant and hardwired in the driver for TPM2, and
> the sysfs file format does not follow the one-value-per-file
> rule.
>
> So it doesn't display anything useful. In TPM2 mode all the timeouts
> are constant and known, so I'd rather see it go away.
>
> > With all the problems we had with TPM 1.2 TPM's wrong timeouts and
> > showing them in sysfs, why not show them for TPM2 as well?
>
> We had problems with devices reporting the wrong timeout from their
> cap queries - that isn't possible in TPM2.
>
> Both of these values should live in debugfs anyhow.
>
> It would be nice to start with a fresh set of correct sysfs files for
> TPM2, since essentially everything is different about the userspace
> interface we can safely make a breaking change here.
I'll drop timeouts and durations. It's easy to add them later if they
are needed.
> Jason
/Jarkko
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