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

Jarkko Sakkinen
2017-08-15T06:09:38Z

On Mon, Aug 14, 2017 at 08:12:53AM -0400, Mimi Zohar wrote:
> 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

That would work for me.

/Jarkko