Re: kern/55286: Kernel messages cause loss of serial console input

[Valery Ushakov <uwe%stderr.spb.ru@localhost>]

The following reply was made to PR kern/55286; it has been noted by GNATS.

From: Valery Ushakov <uwe%stderr.spb.ru@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: kern/55286: Kernel messages cause loss of serial console input
Date: Mon, 25 May 2020 03:18:46 +0300

 On Sun, May 24, 2020 at 13:55:03 +0000, Andreas Gustafsson wrote:
 
 >  The code I'd like to delete is in com_common_putc() and is intended
 >  for situations such as early startup where interrupts are not yet
 >  enabled, or late shutdown when they have already been disabled.
 [...]
 >  > I need it.
 >  
 >  Sure, but do you need it specifically in the case when serial
 >  interrupts are disabled and the kernel is not polling for console
 >  input but is printing something to the console?  That is the only
 >  case that deleting this code will break.
 
 How does your original test end up in a state like that to trigger
 this bug?  Kernel message being printed with polled code and steals
 the input?  In that case isn't the right fix to only do readahead when
 interrupts are disabled?
 
 -uwe