Re: [PATCH 4/6] arm: mach-omap2: remove "OMAP_DEVICE_NO_IDLE_ON_SUSPEND"check

[Sourav Poddar]

Hi Kevin,
On Friday 19 April 2013 03:33 AM, Kevin Hilman wrote:
> Sourav Poddar<sourav.poddar@xxxxxx>  writes:
>
> > On Thursday 18 April 2013 11:35 PM, Kevin Hilman wrote:
> > > Sourav Poddar<sourav.poddar@xxxxxx>   writes:
> > >
> > > > Remove the "OMAP_DEVICE_NO_IDLE_ON_SUSPEND" check, since UART was the only one making
> > > > use of it. Now serial core/driver takes care of the case when "no_console_suspend"
> > > > is used in the bootargs and you need to keep the clock enable for console even while suspend.
> > > >
> > > > Signed-off-by: Sourav Poddar<sourav.poddar@xxxxxx>
> > > NAK.  This patch will break many things...
> > >
> > > > ---
> > > >    arch/arm/mach-omap2/omap_device.c |    7 +------
> > > >    1 files changed, 1 insertions(+), 6 deletions(-)
> > > >
> > > > diff --git a/arch/arm/mach-omap2/omap_device.c b/arch/arm/mach-omap2/omap_device.c
> > > > index 381be7a..d6dce8f 100644
> > > > --- a/arch/arm/mach-omap2/omap_device.c
> > > > +++ b/arch/arm/mach-omap2/omap_device.c
> > > > @@ -620,11 +620,8 @@ static int _od_suspend_noirq(struct device *dev)
> > > >    	ret = pm_generic_suspend_noirq(dev);
> > > >
> > > >    	if (!ret&&   !pm_runtime_status_suspended(dev)) {
> > > > -		if (pm_generic_runtime_suspend(dev) == 0) {
> > > > -			if (!(od->flags&   OMAP_DEVICE_NO_IDLE_ON_SUSPEND))
> > > > -				omap_device_idle(pdev);
> > > Why did you remove the omap_device_idle() here?
> > This patch is used along with patch3 to get rid of the issue. I posted
> > them as a
> > seperate patch beacuse of the subject line as one goes under drivers/*
> > and the other
> > arm/mach-omap2/*..
> >
> > This check was only valid for UART, and if od->flags is set to the
> > "OMAP_DEVICE_NO_IDLE_ON_SUSPEND" flag, then UART will not be idled.
> correct, but *every other device* would be idled (if not already idle.)
>
> > But now, we no longer depend on od->flag value to prevent idling of
> > our console UART as the prepare/complete apis will take care of them.
> Right, so removing the check on od->flags is fine, but what I asked
> about is why you removed the omap_device_idle() call.
>
> Remember that this code is called for *every* omap_device during
> suspend, not just UART.
>
> What you did stops *every* device from being idled during suspend.
>
> You didn't read my whole message.  Specifically this part:
Yes, got your point. omap_device_idle should not be called only
for console uart.

Just did a quick testing by including the following hunk on top of my 
patch series..

diff --git a/arch/arm/mach-omap2/omap_device.c 
b/arch/arm/mach-omap2/omap_device.c
index c226946..7480e87 100644
--- a/arch/arm/mach-omap2/omap_device.c
+++ b/arch/arm/mach-omap2/omap_device.c
@@ -617,8 +617,10 @@ static int _od_suspend_noirq(struct device *dev)
        ret = pm_generic_suspend_noirq(dev);

        if (!ret && !pm_runtime_status_suspended(dev)) {
-               if (pm_generic_runtime_suspend(dev) == 0)
+               if (pm_generic_runtime_suspend(dev) == 0) {
+                       omap_device_idle(pdev);
                        od->flags |= OMAP_DEVICE_SUSPENDED;
+               }
        }

        return ret;
@@ -631,6 +633,7 @@ static int _od_resume_noirq(struct device *dev)

        if ((od->flags & OMAP_DEVICE_SUSPENDED) &&
            !pm_runtime_status_suspended(dev)) {
+               omap_device_enable(pdev);
                od->flags &= ~OMAP_DEVICE_SUSPENDED;
                pm_generic_runtime_resume(dev);
        }
And found the wakeup from UART is no more functional.
So, the omap_device_idle gets called for console UART also, thereby
preventing the "no_idle_on_suspend" theory.

Hence, merely putting prepare/complete callback the way I did is not 
helping.
We need to delete omap_device_idle also, which I agree is not correct.
So, we need a way to bypass this "omap_device_idle"
call for console UART. ?
What my understanding was that after modifying serial driver,
bypass the entire hunk[1] for console UART?


> > > Note that the check is for when the flag is *not* set, so this patch
> > > changes behavior for all the drivers that do not use
> > > _NO_IDLE_ON_SUSPEND.  I think that's the opposite of what you intended.
> Kevin

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