Re: kern/54317: System hang during boot

[Thomas Klausner <wiz%NetBSD.org@localhost>]

The following reply was made to PR kern/54317; it has been noted by GNATS.

From: Thomas Klausner <wiz%NetBSD.org@localhost>
To: matthew green <mrg%eterna.com.au@localhost>
Cc: NetBSD bugtracking <gnats-bugs%NetBSD.org@localhost>
Subject: Re: kern/54317: System hang during boot
Date: Tue, 2 Jul 2019 19:52:01 +0200

 I did my tests with 8.99.46 because that was still installed.
 
 On Mon, Jun 24, 2019 at 07:11:19AM +1000, Matthew Green wrote:
 > Thomas Klausner writes:
 > > On Sun, Jun 23, 2019 at 10:34:38PM +1000, Matthew Green wrote:
 > > > >  So I tried disableing all radeon* and radeondrmkmsfb* and radeonfb*
 > > > > with userconf, but that didn't help.
 > > > 
 > > > what happened?  i assume vga attached instead, and whatever the
 > > > problem is remains, ie, probably not the gpu?
 > > 
 > > I got a text console (I didn't check the dmesg for details, but I can
 > > if you want to know something in particular) and it hung in the same
 > > place, after the line about setting tty flags.
 > 
 > hmmm, try turning off ttyflags in rc.conf.  this may be
 > triggering some problem ...
 > 
 > alternatively, boot single user and run /etc/rc.d/ttyflags
 > and see if that hangs,
 
 It did.
 
 > if it does, next attempt would be to
 > comment various lines in /etc/ttys until ttyflags does _not_
 > hang...
 > 
 > > > i would just keep disabling drivers -- there are a *lot* that
 > > > attach something -- and see if anything helps.
 > > 
 > > There are a lot of drivers in GENERIC - are there any you would try
 > > disabling first?
 > 
 > hmmm, this might need a kernel or smarts in user conf:
 > 
 > - disable @ acpi attachments (eg, pckbc)
 > - disable com(4)
 
 Disabling "com0 at isa*" makes the boot finish successfully.
 
 Alternatively, I can comment out the tty0* lines in /etc/ttys to make
 the build succeed.
 
 Thanks for the hints!
 
 Should we disable "com0 at isa*" in GENERIC?
  Thomas