Re: Re: [tpmdd-devel] [PATCH] tpm: improve tpm_tis send() performance by ignoring burstcount

Mimi Zohar
2017-08-14T12:13:11Z

On Mon, 2017-08-14 at 13:56 +0300, Jarkko Sakkinen wrote:

> > > Since the main concern about this change is breaking old systems that
> > > might potentially have other peripherals hanging off the LPC bus, can
> > > we define a new Kconfig option, with the default as 'N'?
> > >
> > > Mimi
> >
> > I guess that could make sense but I would like to hear feedback first.
> >
> > /Jarkko
>
> And I'm worried would that it'd be left for many years to come as an
> option. I do not have any metrics what portion of hardware in the field
> would break if this is turned on.
>
> It would slow down kernel testing as I would have to run tests for the
> driver with that option turned on and off because it is a major shift
> from how driver functions. And I have zero idea how long I would go on
> doing this.
>
> One maybe a little bit better option would be to have a sysfs attribute
> for this functionality (disable_burst_count). What do you think about
> that?

That works! So we'll define a module_param named disable_burst_count,
which can be specified on the boot command line.

Mimi