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From: Peter Hurley <peter@hurleysoftware.com>
To: balbi@ti.com, Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	Tony Lindgren <tony@atomide.com>,
	linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	mika.westerberg@linux.intel.com
Subject: Re: [PATCH 4/5] tty: serial: 8250 core: add runtime pm
Date: Thu, 17 Jul 2014 11:31:59 -0400	[thread overview]
Message-ID: <53C7EC6F.6060902@hurleysoftware.com> (raw)
In-Reply-To: <20140716160614.GI1365@saruman.home>

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

  parent reply	other threads:[~2014-07-17 15:32 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-16 14:44 [PATCH v4] 8250-core based serial driver for OMAP Sebastian Andrzej Siewior
2014-07-16 14:44 ` [PATCH 1/5] tty: serial: 8250 core: provide a function to export uart_8250_port Sebastian Andrzej Siewior
2014-07-16 14:45 ` [PATCH 2/5] tty: serial: 8250 core: allow to overwrite & export serial8250_startup() Sebastian Andrzej Siewior
2014-07-16 14:45 ` [PATCH 3/5] tty: serial: 8250 core: allow to set ->throttle / ->unthrottle callbacks Sebastian Andrzej Siewior
2014-07-16 14:45 ` [PATCH 4/5] tty: serial: 8250 core: add runtime pm Sebastian Andrzej Siewior
2014-07-16 15:16   ` Felipe Balbi
2014-07-16 15:54     ` Sebastian Andrzej Siewior
2014-07-16 16:06       ` Felipe Balbi
2014-07-16 16:40         ` Sebastian Andrzej Siewior
2014-07-16 16:46           ` Felipe Balbi
2014-07-17 15:31         ` Peter Hurley [this message]
2014-07-17 15:43           ` Sebastian Andrzej Siewior
2014-07-17 16:02             ` Felipe Balbi
2014-07-17 16:06               ` Sebastian Andrzej Siewior
2014-07-17 16:18                 ` Felipe Balbi
2014-07-18  8:35                   ` Sebastian Andrzej Siewior
2014-07-18 15:31                     ` Felipe Balbi
2014-07-18 15:53                       ` Peter Hurley
2014-07-18 16:02                         ` Felipe Balbi
2014-07-16 14:45 ` [PATCH 5/5] tty: serial: Add 8250-core based omap driver Sebastian Andrzej Siewior
2014-07-17  7:09   ` Tony Lindgren
2014-07-17  7:42     ` Sebastian Andrzej Siewior
2014-07-17  8:12       ` Tony Lindgren
2014-07-17 10:06         ` Sebastian Andrzej Siewior
2014-07-18  6:24           ` Tony Lindgren
2014-07-21  9:35             ` Tony Lindgren
2014-08-13 16:20               ` Sebastian Andrzej Siewior
2014-08-13 16:37                 ` Tony Lindgren
2014-07-17 14:54   ` Felipe Balbi
2014-07-17 15:11     ` Sebastian Andrzej Siewior
2014-07-17 16:04       ` Felipe Balbi

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