Re: [PATCH] OMAPDSS: Check if RPM enabled before trying to change state

On 27 June 2012 00:14, Tomi Valkeinen [off-list ref] wrote:

On Tue, 2012-06-26 at 22:31 +0530, Jassi Brar wrote:

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But if pm_runtime_get_sync() returns an error, it means the HW has not
been resumed successfully, and is not operational,

Not always. The HW could be in RPM_ACTIVE state while PM on it could
be disabled, if the returned error is -EACCESS.   And
pm_runtime_enabled() only catches a potential -EACCESS.

True. But the HW could also be in disabled state. And that would lead to
a crash when accessing the registers.

It is not a fatal error if pm_runtime_get returns -EACCES, but we sure
shouldn't ignore it (or avoid it with pm_runtime_enabled()), but handle
it. In some rare cases it could be ok to get -EACCES, but that's a
special case, not standard.

You are mixing up generic concepts with what we have in omapdss.
Believe me, I do understand it's bad to proceed without caring for
returned _errors_.
The way omapdss is organized -EACCESS is _not_ an  error, it just
denotes PM is disabled on the device and that DISPC is in RPM_ACTIVE
is backed by the fact that HDMI always hold a reference between
resume-suspend and DISPC goes to suspend last and resume first.

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BTW, I just tested your patch and it worked for me as well. But as
suspected, it doesn't help the stack spew of CONFIG_PM_RUNTIME:=n

So I understand, I only need to resend the other three patches ?

Yes, please.

OK, will do today later.

Regards.