Re: pre-patch-2.0.31 try_to_free_page() messages

Dean Gaudet (dgaudet-list-linux-kernel@arctic.org)
Wed, 4 Jun 1997 16:09:28 -0700 (PDT)

On Sun, 1 Jun 1997 tytso@mit.edu wrote:
> There are known interrupt latency problems that cause characters to be
> dropped by the UART, before the serial driver has a chance to get the
> characters. This was intential due to some broken IDE controllers that
> could cause MASSIVE FILESYSTEM DAMAGE if the problem was not worked
> around.

I've been running the Interrupt+Serial+Overrun patch from
<http://mosquitonet.Stanford.EDU/software/LinuxChanges.html> and I've been
using hdparm -u 1, and I still get overruns. Not nearly as many, but I
still do get overruns. Granted, Stuart's patch changes serial handling
greatly, so this may not be entirely true of the standard kernel. But I
highly suspect it is still true of the standard kernel.

This is at 115200 on a thinkpad 560 with a megahertz pcmcia modem.

Does the 2.1 plan include integrating the RT-Linux code? I heard that a
while back, but I'm not sure it's the case. If so that can be used to
help this situation a lot.

Dean