lkml.org 
[lkml]   [2008]   [Jan]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] serial: remove "too much work for irq" printk
On Sat 2008-01-12 21:24:57, Alan Cox wrote:
> On Sat, 12 Jan 2008 15:15:43 -0500
> Benjamin LaHaise <bcrl@kvack.org> wrote:
>
> > When using kvm with a serial console, the serial driver will print out
> > "too much work for irq4" on any heavy activity (ie vi on a file repainting
> > the terminal). This message is entirely spurious, as output continues to
> > work fine. Remove the message as it corrupts screen output and is far too
> > easy to trigger.
>
> NAK. This is a qemu/kvm emulation bug. The real check is there to catched
> jammed IRQs and combined with the IRQ bug handling nowdays does actually
> do the intended job.
>
> Our serial port code (correctly) interprets a continuous stream of bytes
> at an impossible bit rate as an error. KVM should be emulating to some
> extent at least the timing on serial interfaces or using a virtualised
> interface.

How can you tell apart impossible bit rate from really slow CPU, or
maybe just an SMI storm, or heavy busmaster DMA?

Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html


\
 
 \ /
  Last update: 2008-01-13 23:05    [W:0.046 / U:0.300 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site