[PATCH 4/5] tty: serial: 8250 core: add runtime pm
Sebastian Andrzej Siewior
bigeasy at linutronix.de
Wed Jul 16 09:40:01 PDT 2014
On 07/16/2014 06:06 PM, Felipe Balbi wrote:
>>> well, other than in probe and other functions which need to
>>> make sure clocks are on, but it seems unnecessary to
>>> enable/disable in every function.
>> What do you have in mind? Do you plan to let the uart on while
>> the minicom is attached but is doing nothing? In that case,
>> ->startup() and ->shutdown() should be enough.
> no the idea was to keep it on for as long as it's transferring
> characters and idle it otherwise, if that can't be done easily,
> then I guess your way is the only way.
But maybe we have to add some additional logic here to keep it up for
the transfer. I've been just (maybe over)thinking: If you send 300
bytes over DMA via 300 baud it should take 10 seconds. The PM-timeout
could hit before the transfer is complete.
Same thing with hw-flowcontrol where you could get stalled for a few
However it doesn't seem to be a problem in current omap-serial driver.
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