From mboxrd@z Thu Jan 1 00:00:00 1970 From: balbi@ti.com (Felipe Balbi) Date: Fri, 18 Jul 2014 11:02:09 -0500 Subject: [PATCH 4/5] tty: serial: 8250 core: add runtime pm In-Reply-To: <53C942F1.2000408@hurleysoftware.com> References: <53C6A050.2050409@linutronix.de> <20140716160614.GI1365@saruman.home> <53C7EC6F.6060902@hurleysoftware.com> <20140717154300.GA16623@linutronix.de> <20140717160206.GI10459@saruman.home> <53C7F4A3.5080508@linutronix.de> <20140717161848.GK10459@saruman.home> <53C8DC3E.3020701@linutronix.de> <20140718153116.GN24914@saruman.home> <53C942F1.2000408@hurleysoftware.com> Message-ID: <20140718160209.GQ24914@saruman.home> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Jul 18, 2014 at 11:53:21AM -0400, Peter Hurley wrote: > On 07/18/2014 11:31 AM, Felipe Balbi wrote: > >On Fri, Jul 18, 2014 at 10:35:10AM +0200, Sebastian Andrzej Siewior wrote: > >>>On 07/17/2014 06:18 PM, Felipe Balbi wrote: > >>> > >>>>> >>No, this is okay. If you look, it checks for "up->ier & > >>>>> >>UART_IER_THRI". On the second invocation it will see that this > >>>>> >>bit is already set and therefore won't call get_sync() for the > >>>>> >>second time. That bit is removed in the _stop_tx() path. > >>>> > > >>>> >oh, right. But that's actually unnecessary. Calling > >>>> >pm_runtime_get() multiple times will just increment the usage > >>>> >counter multiple times, which means you can call __stop_tx() > >>>> >multiple times too and everything gets balanced, right ? > >>> > >>>No. start_tx() will be called multiple times but only the first > >>>invocation invoke pm_runtime_get(). Now I noticed that I forgot to > >right, but that's unnecessary. You can pm_runtime_get() every time > >start_tx() is called. Just make sure to put everytime stop_tx() is > >called too. > > The interface is asymmetric. > > start_tx() may be invoked multiple times for which only 1 interrupt > will occur, and thus only invoke __stop_tx() once. alright, thanks for the info. -- balbi -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 819 bytes Desc: Digital signature URL: