Re: Provide /sys/../ec with read/write access and some cleanups

From: Henrique de Moraes Holschuh
Date: Thu Jul 01 2010 - 19:27:48 EST


On Thu, 01 Jul 2010, Thomas Renninger wrote:
> On Thursday 01 July 2010 06:22:39 pm Henrique de Moraes Holschuh wrote:
> > On Thu, 01 Jul 2010, Thomas Renninger wrote:
> > > These patches are diffed against the test branch of the ACPI tree, but
> > > also patch fine with 2.6.35-rc3.
> > >
> > > I thought about tainting the kernel if someone writes to the EC, but as
> > > userspace can also write to graphics IO, PCI config or MSRs, it shouldn't
> > > matter that much.
> > > Eventually this should still be added (by a separate patch), one can
> > > easily confuse the EC to not switch on the fans anymore.
> > >
> > > A small tool to read out and write to /sys/devices/system/ec/*/io can be
> > > found here:
> > > ftp://ftp.suse.com/pub/people/trenn/sources/ec/ec_access.c
> > >
> > > Len: Can you apply these into your test branch and schedule them for
> > > linux-next and 2.6.36 if there are no objections, please.
> >
> > I am just wondering if we shouldn't have this in debugfs instead of regular
> > /sys. Do you envision *production* use of this facility, or should it just
> > be something to use for debugging and hacking?
> Only for debugging and hacking. Apps must not use it for production.
> On the one hand I agree, on the other hand side I think the EC somehow
> fits into /sys/devices/system/ec. I don't have a strong opion on that, though.

You can have the ec metadata in sys, and the EC direct access in
debugfs, for example...

--
"One disk to rule them all, One disk to find them. One disk to bring
them all and in the darkness grind them. In the Land of Redmond
where the shadows lie." -- The Silicon Valley Tarot
Henrique Holschuh
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