Subject: Re: Handling BREAK on serail console in com dirver?
To: Valeriy E. Ushakov <>
From: Bill Studenmund <>
List: tech-kern
Date: 10/07/2001 05:57:00
On Sun, 7 Oct 2001, Valeriy E. Ushakov wrote:

> I have a bad cold that makes my mind rather hazy, so can someone
> familiar with ns16x50 please correct me if I'm wrong.
> In com_enable_debugport and com_shutdown we set Interrupt Enable
> Register to IER_ERXRDY with a comment that for serial console we want
> an interrupt on BREAK.  However my reading of the ns16550 docs is that
> to get an interrupt on BREAK we need to set it to IER_ERLS.

First off, have you tried it with the current code? IF it works, don't
change it. :-)

To test, run w/ a serial console but with no getty running on it (so the
port won't be open). Then try sending a break. You should get into ddb.

What exactly doe ERXRDY do?

Take care,