Subject: Re: Serial driver hangs
From: Paul Fulghum <paulkf@microgate.com>
To: Russell King <rmk+lkml@arm.linux.org.uk>
Cc: Roland =?ISO-8859-1?Q?Ca=DFebohm?= 
	<roland.cassebohm@VisionSystems.de>,
       Linux Kernel list <linux-kernel@vger.kernel.org>
In-Reply-To: <20040928221600.D14747@flint.arm.linux.org.uk>
References: <200409281734.38781.roland.cassebohm@visionsystems.de>
	 <1096405831.2513.37.camel@deimos.microgate.com>
	 <20040928221600.D14747@flint.arm.linux.org.uk>
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Date: Tue, 28 Sep 2004 18:03:03 -0500
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On Tue, 2004-09-28 at 16:16, Russell King wrote:
> On Tue, Sep 28, 2004 at 04:10:31PM -0500, Paul Fulghum wrote:
> Some 16x50 ports (most of the ones higher than 16550A) have auto flow
> control, so if this is enabled you really don't want to drop bytes in
> the FIFO on the floor.

The alternative is to implement a flow control
mechanism between the flip buffer layer and
the tty drivers to (at the very least)
enable/disable receive interrupts.

Since the flip buffer implementation is probably
going to need rework anyways (eventually) along
with the other tty locking issues, this may not
be a trivial task.

Dropping the bytes is a simple, local fix that
will be more sane than the current
behavior of locking the machine.

A more optimized solution is likely to take a while.

-- 
Paul Fulghum
paulkf@microgate.com


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