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From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] amba-pl011: support hardware flow control
Date: Wed, 10 Feb 2010 08:30:12 +0000	[thread overview]
Message-ID: <20100210083012.GA11701@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <20100210011637.GA8683@shareable.org>

On Wed, Feb 10, 2010 at 01:16:37AM +0000, Jamie Lokier wrote:
> Russell King - ARM Linux wrote:
> > This means that when the kernel's buffers fill up, the kernel calls
> > down to the serial core layer to throttle the input.  This then
> > calls into the set_mctrl function to de-assert RTS.  However, because
> > the hardware ignores the requested software state, the RTS signal
> > is not de-asserted, and the remote end continues sending data.
> > 
> > So, enabling hardware auto-RTS is bad news - you will lose data if
> > the application stops reading data.
> 
> Surely the driver can just stop reading from the UART when the
> kernel's buffers are full and hardware-RTS is enabled.  Then the
> hardware will deassert RTS itself.

I'll let you work out how to implement that.

  reply	other threads:[~2010-02-10  8:30 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-02-08 13:41 [PATCH] amba-pl011: support hardware flow control Rabin Vincent
2010-02-08 13:51 ` Russell King - ARM Linux
2010-02-09 14:30   ` Rabin VINCENT
2010-02-09 18:01     ` Russell King - ARM Linux
2010-02-09 22:14     ` Russell King - ARM Linux
2010-02-10  1:16       ` Jamie Lokier
2010-02-10  8:30         ` Russell King - ARM Linux [this message]
2010-02-10 10:12           ` Jamie Lokier
2010-02-10 13:45         ` Rabin VINCENT
2010-02-10 20:25           ` Russell King - ARM Linux
2010-02-11 16:56             ` Rabin VINCENT
2010-02-12  9:01             ` Linus Walleij
  -- strict thread matches above, loose matches on Subject: below --
2010-02-02  3:32 Rabin Vincent

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