lkml.org 
[lkml]   [2014]   [Jul]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2 14/16] cpufreq: Add cpufreq driver for Tegra124
On Wed, Jul 23, 2014 at 01:55:57PM +0530, Viresh Kumar wrote:
> On 23 July 2014 12:54, Thierry Reding <thierry.reding@gmail.com> wrote:
> > ARM_TEGRA_CPUFREQ is still optional, so the select only applies when the
> > Tegra cpufreq driver is enabled. This is mostly just out of convenience,
> > though. The Tegra cpufreq driver uses the generic CPU0 cpufreq driver so
> > a select will automatically pull in the necessary dependency. With a
>
> Not necessarily. cpufreq-cpu0 can have few unmet dependency. And so
> there are chances that tegra driver is compiled but cpufreq-cpu0 isn't as
> we didn't mention it as a *hard* dependency.
>
> And so at boot, there wouldn't be any cpufreq support even when tegra's
> cpufreq driver is available.
>
> Though, menuconfig may give some warnings no such situations.
>
> > "depends on" the Tegra cpufreq driver only becomes available after
> > you've selected GENERIC_CPUFREQ_CPU0, which is somewhat unintuitive.
> >
> > To illustrate with an example: as a user, I want to enable CPU frequency
> > scaling on Tegra. So I use menuconfig to navigate to the "CPU Frequency
> > scaling" menu (enable it if not available yet) and look for an entry
> > that says "Tegra". But I can't find it because it's hidden due to the
> > lack of GENERIC_CPUFREQ_CPU0. That the Tegra CPU frequency driver uses a
> > generic driver is an implementation detail that users shouldn't have to
> > be aware of.
>
> Don't know, the guy compiling out stuff should be knowledgeable enough to
> have a look why tegra cpufreq entry isn't shown in menu. As, probably the
> above problem I mentioned looks to be of more significance than this one,
> atleast to me :)
>
> And, another thing to mention is that CONFIG_TEGRA_CPUFREQ is valid
> for earlier platforms as well and so a select/depends wouldn't be valid for
> earlier platforms. We probably need another Kconfig entry here.

Yes, sounds like a new Kconfig entry for this specific driver would be a
better approach and should remove all the above concerns.

Thierry
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2014-07-23 16:21    [W:0.708 / U:0.488 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site