Re: [PATCH] serial_core: avoid Break bouncing

From: Mauro Carvalho Chehab
Date: Thu Nov 12 2009 - 13:22:49 EST


Em Thu, 12 Nov 2009 17:56:49 +0000
Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> escreveu:

> On Thu, 12 Nov 2009 14:05:04 -0200
> Mauro Carvalho Chehab <mchehab@xxxxxxxxxx> wrote:
>
> > From: Eran Liberty <liberty@xxxxxxxxxxxx>
> >
> > On some boxes, Break signal bounces, causing sysrq code to fail with some
> > serial interfaces.
> >
> > A solution were posted on LKML in 2008:
> > http://lkml.indiana.edu/hypermail/linux/kernel/0809.2/0730.html
> >
> > However, the fix weren't applied upstream.
>
> Because it was NAKked at the time as it seemed to be a bug in Eran's
> hardware platform not a generic problem and also because it breaks
> autobauding on break as used by some (particularly older) software.
>
> It's still NAKked and it would be helpful if people resubmitting old
> stuff also looked through the thread attached the original submission.

I did, but I haven't find any nack at the public archives I've checked. My
fault. Sorry about that.

> You seem to have a single case of a user with some kind of buggy uart or
> possibly other weirdness going on. That's probably worth investigating
> more deeply but the patch NAKked before is not the solution due to its
> side effects

I'll do a deeper analysis and come back with a patch only if I discover
something new about this issue.
>
> (also btw it'll upset other people who script their sysrq stuff including
> breaks and don't expect strange timing limits)
>
> NAK again


--

Cheers,
Mauro
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