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From: Wolfram Sang <w.sang@pengutronix.de>
To: Claudio Scordino <claudio@evidence.eu.com>
Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
	Alan Cox <alan@linux.intel.com>,
	Juergen Beisert <jbe@pengutronix.de>,
	Matthias Fuchs <mfuchs@ma-fu.de>
Subject: Re: [PATCH 5/8] serial: 8250: reject delaying RTS with RS485
Date: Thu, 17 Nov 2011 11:14:26 +0100	[thread overview]
Message-ID: <20111117101426.GD2535@pengutronix.de> (raw)
In-Reply-To: <4EC4D72F.8030702@evidence.eu.com>

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> The delay must not necessarily be done by hardware. The drivers/tty/serial/crisv10.c 
> driver, for example, delays through a msleep.
> 
> I don't know if having a software delay in this driver can make sense in some particular 
> circumstance.

Uuuh, I would be against software delays for the same reason why we
don't accept software based direction switching: No guarantees. msleep()
might easily delay longer than what was requested. Or are delay_rts
values to be interpreted as "delay at least"?

Regards,

   Wolfram

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

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  reply	other threads:[~2011-11-17 10:14 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-16 16:24 [PATCH 0/8] serial: 8250: support hw-based RS485 direction control (finally!) Wolfram Sang
2011-11-16 16:24 ` [PATCH 1/8] serial: 8250: replace hardcoded 0xbf with #define Wolfram Sang
2011-11-16 16:24 ` [PATCH 2/8] serial: 8250: Add ioctl to enable auto rs485 mode with some Exar UARTs Wolfram Sang
2011-11-17  9:40   ` Claudio Scordino
2011-11-17 10:09     ` Wolfram Sang
2011-11-16 16:24 ` [PATCH 3/8] serial: 8250: save rs485_flags per instance Wolfram Sang
2011-11-16 16:24 ` [PATCH 4/8] serial: 8250: add RX_DURING_TX capability to RS485 mode Wolfram Sang
2011-11-16 16:24 ` [PATCH 5/8] serial: 8250: reject delaying RTS with RS485 Wolfram Sang
2011-11-17  9:43   ` Claudio Scordino
2011-11-17 10:14     ` Wolfram Sang [this message]
2011-11-16 16:24 ` [PATCH 6/8] serial: 8250: update rs485 flags with polarity settings Wolfram Sang
2011-11-16 16:24 ` [PATCH 7/8] serial: 8250: add Exar 16V2750 support Wolfram Sang
2011-11-16 16:24 ` [PATCH 8/8] serial: 8250: fix comment about accessing EMSR Wolfram Sang
2011-11-23 15:03 ` [PATCH 0/8] serial: 8250: support hw-based RS485 direction control (finally!) Wolfram Sang
2011-11-24 16:05   ` Claudio Scordino

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