Messages in this thread | | | Date | Thu, 17 Jul 2014 11:31:59 -0400 | From | Peter Hurley <> | Subject | Re: [PATCH 4/5] tty: serial: 8250 core: add runtime pm |
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On 07/16/2014 12:06 PM, Felipe Balbi wrote: > On Wed, Jul 16, 2014 at 05:54:56PM +0200, Sebastian Andrzej Siewior wrote: >> On 07/16/2014 05:16 PM, Felipe Balbi wrote:
>>> I wonder if you should get_sync() on start_tx() and only >>> put_autosuspend() at stop_tx(). I guess the outcome would be >>> largely the same, no ? >> >> I just opened minicom on ttyS0 and gave a try. start_tx() was invoked >> each time I pressed a key (sent a character). I haven't seen stop_tx() >> even after after I closed minicom. I guess stop_tx() is invoked if you >> switch half-duplex communication. > > that's bad, I expected stop to be called also after each character.
The 8250 core auto-stops tx when the tx ring buffer is empty (except in the case of dma, where stopping tx isn't necessary).
Regards, Peter Hurley
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