RE: [PATCH/RFC 2/2] OMAP: PM: implement context loss count APIs

Vishwanath Sripathy
2010-12-13T13:48:36Z

Paul,

> -----Original Message-----
> From: Paul Walmsley [mailto:paul@pwsan.com]
> Sent: Monday, December 13, 2010 4:13 PM
> To: Vishwanath Sripathy
> Cc: Kevin Hilman; linux-omap@vger.kernel.org
> Subject: RE: [PATCH/RFC 2/2] OMAP: PM: implement context loss count
> APIs
>
> Hello Vishwa,
>
> On Fri, 10 Dec 2010, Vishwanath Sripathy wrote:
>
> > > + count = omap_device_get_context_loss_count(pdev);
> > > + pr_debug("OMAP PM: context loss count for dev %s = %d\n",
> > > + dev_name(dev), count);
> > Shouldn't this implementation be part of omap-pm.c where all the
> OMAP PM
> > functions are to be implemented? I thought omap-pm-noop.c should
> have
> > dummy implementation.
>
> In general, yes. But we also want the code in omap-pm-noop.c not to
> cause
> additional breakage. Unlike most of the other functions in this file,
if
> the context loss count function doesn't do something minimally useful,
> then
> the system is going to break badly. You've probably seen this thread:
>
> http://www.mail-archive.com/linux-
> omap@vger.kernel.org/msg40079.html
>
> (By the way, the reason why I think we shouldn't use the approach
> described in
>
> http://www.mail-archive.com/linux-
> omap@vger.kernel.org/msg40101.html
>
> is because I suspect it is going to seriously damage retention idle
> performance. For example, the HSMMC driver resets its entire IP block
in
> its context restore function...)
>
> But to confirm your general point, yes, in general, further functional
> development of the OMAP PM code should take place outside the no-op
> file.
> Hopefully, at some point, we'll be able to drop the no-op file. Once
> there is a useful replacement, we should be able to switch to it as a
> default.
I have no issues with the implementation and I agree. All I am saying is
that why can't this implementation be added in omap-pm.c and compile this
file instead of omap-pm-noop.c when OMAP_PM is enabled. I believe this
function is useful when off mode is enabled which means OMAP_PM is
enabled.

Vishwa
>
>
> - Paul