linux-kernel - RE: [RFT/PATCH] serial: omap: prevent resume if device is not suspended.

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Date:	Fri, 12 Oct 2012 17:29:55 +0000
From:	"Poddar, Sourav" <sourav.poddar@...com>
To:	Russell King - ARM Linux <linux@....linux.org.uk>,
	Kevin Hilman <khilman@...prootsystems.com>
CC:	Paul Walmsley <paul@...an.com>, "Balbi, Felipe" <balbi@...com>,
	"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
	"tony@...mide.com" <tony@...mide.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"Shilimkar, Santosh" <santosh.shilimkar@...com>,
	"linux-serial@...r.kernel.org" <linux-serial@...r.kernel.org>,
	"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"alan@...ux.intel.com" <alan@...ux.intel.com>
Subject: RE: [RFT/PATCH] serial: omap: prevent resume if device is not
	suspended.

Hi Russell,
________________________________________
From: Russell King - ARM Linux [linux@....linux.org.uk]
Sent: Friday, October 12, 2012 10:12 PM
To: Kevin Hilman
Cc: Poddar, Sourav; Paul Walmsley; Balbi, Felipe; gregkh@...uxfoundation.org; tony@...mide.com; linux-kernel@...r.kernel.org; Shilimkar, Santosh; linux-serial@...r.kernel.org; linux-omap@...r.kernel.org; linux-arm-kernel@...ts.infradead.org; alan@...ux.intel.com
Subject: Re: [RFT/PATCH] serial: omap: prevent resume if device is not  suspended.

On Fri, Oct 12, 2012 at 09:35:54AM -0700, Kevin Hilman wrote:
> Sourav <sourav.poddar@...com> writes:
> > diff --git a/drivers/tty/serial/omap-serial.c
> > b/drivers/tty/serial/omap-serial.c
> > index 6ede6fd..3fbc7f7 100644
> > --- a/drivers/tty/serial/omap-serial.c
> > +++ b/drivers/tty/serial/omap-serial.c
> > @@ -1414,6 +1414,7 @@ static int __devinit serial_omap_probe(struct
> > platform_device *pdev)
> >         INIT_WORK(&up->qos_work, serial_omap_uart_qos_work);
> >
> >         platform_set_drvdata(pdev, up);
> > +       pm_runtime_set_active(&pdev->dev);
>
> NAK.
>
> This will obviously break platforms where the UARTs are not active
> before driver loads.

I thought I had proposed a solution for this issue, which was this
sequence:

        omap_device_enable(dev);
        pm_runtime_set_active(dev);
        pm_runtime_enable(dev);

Yes, I can understand people not liking the omap_device_enable()
there, but I also notice that the email suggesting that never got a
reply either - not even a "I tried this and it doesn't work" or "it
does work".

Sorry for the late reply on this. I tried this sequence and it worked perfectly fine on
panda and beagle. 

As such, it seems this issue isn't making any progress as we had
already established that merely doing a "pm_runtime_set_active()"
before "pm_runtime_enable()" was going to break other platforms.

 I was  trying to analyse your explanations on this and since omap_device_enable is not generally 
recommended,  I was trying to see if anything else can be done to get around this.

I send this patch for N800 testing so  as to see how it behaves. (We are suspecting that there might be
mux setting issue also with N800).   

~Sourav
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