I know, we will use dummy RX data to wake up.
The question is that is it ok to call pm_runtime_get_sync() in spin_lock context and interrupt context.
You can see all the uart operations are protected by spin_lock.
spin_lock_irqsave(&uport->lock, flags);
uport->ops->stop_rx(uport);
spin_unlock_irqrestore(&uport->lock, flags);
Thanks,
Huiquan
-----Original Message-----
From: Sebastian Andrzej Siewior [mailto:bigeasy@xxxxxxxxxxxxx]
Sent: Monday, March 2, 2015 8:51 PM
To: Zhong, Huiquan; linux-serial@xxxxxxxxxxxxxxx
Cc: mika.westerberg@xxxxxxxxxxxxxxx; alan@xxxxxxxxxxxxxxx; tony@xxxxxxxxxxx
Subject: Re: tty: serial: 8250_core runtime pm issue
On 03/02/2015 10:37 AM, Zhong, Huiquan wrote:
> Anyone have some idea on this, Is it ok to enable Full RPM for 8250 driver?
I don't remember seeing those backtraces but I could double check if time permits.
Currently only omap (that is 8250-omap) is using this kind of RPM. Be aware that if you enable it in the driver (and userland) then it will switch the UART off (or put in PM) even if the /dev/ttySx node is open or the UART is used as console. The result is that we usually lose the first RX character (sometimes more, depending on speed) on the console because this is used to trigger the wake up event and to bring the HW back operational.
>
> Thanks,
>
> Huiquan
Sebastian
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