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From: Alex Williamson <alex.williamson@hp.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: rmk+serial@arm.linux.org.uk, linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] 8250 UART backup timer
Date: Tue, 27 Jun 2006 13:32:11 -0600	[thread overview]
Message-ID: <1151436731.5600.50.camel@lappy> (raw)
In-Reply-To: <44A183C5.6050002@zytor.com>

On Tue, 2006-06-27 at 12:15 -0700, H. Peter Anvin wrote:
> Alex Williamson wrote:
> >    The patch below works around a minor bug found in the UART of the
> > remote management card used in many HP ia64 and parisc servers (aka the
> > Diva UARTs).  The problem is that the UART does not reassert the THRE
> > interrupt if it has been previously cleared and the IIR THRI bit is
> > re-enabled.  This can produce a very annoying failure mode when used as
> > a serial console, allowing a boot/reboot to hang indefinitely until an
> > RX interrupt kicks it into working again (ie. an unattended reboot could
> > stall). 
> 
> I have seen this same bug in soft UART IP from "a major vendor."

   If you get a chance to try, please let us know if this patch works
there too or needs any additional tweaking to make it work there.
Thanks,

	Alex

-- 
Alex Williamson                             HP Open Source & Linux Org.


  reply	other threads:[~2006-06-27 19:32 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-06-27 19:04 [PATCH] 8250 UART backup timer Alex Williamson
2006-06-27 19:15 ` H. Peter Anvin
2006-06-27 19:32   ` Alex Williamson [this message]
2006-09-13 20:18   ` Aristeu Sergio Rozanski Filho
2006-07-05  3:39 ` Alex Williamson
2006-09-13 20:16   ` Aristeu Sergio Rozanski Filho

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