At Mon, 06 Jul 2020 13:13:03 -0700, "Greg A. Woods" <[email protected]> wrote: Subject: Re: NetBSD-7.0 boots OK and NetBSD-8.0 hangs/crashes during boot on a MacBook7,1 > > Or indeed any device with any kind of USB port, e.g. a laptop.
Oh, and I wanted to mention something else that I'd forgotten about but
stumbled across again the other day while debugging servers:
Xen supports writing console messages to a special kind of USB port:
"console=dbgp" indicates that Xen should use a USB debug port.
http://xenbits.xenproject.org/docs/4.11-testing/misc/xen-command-line.html
There's more about it in this thread:
https://lists.xenproject.org/archives/html/xen-devel/2009-03/msg00436.html
https://lists.xenproject.org/archives/html/xen-devel/2009-03/msg00458.html
Further of interest is that Xen also supports writing to both a COM port
and the "vga" console simultaneously. Indeed it may support writing to
"dbgp" at the same time as well. This is something I looked into for
NetBSD/i386 some time ago, but never got it fully working. To me I
think it would be super incredibly valuable for the boot code to be able
to talk to both a serial port and the "pc" console simultaneously. It
is less important for the kernel to do so, but it still would be nice.
--
Greg A. Woods <[email protected]>
Kelowna, BC +1 250 762-7675 RoboHack <[email protected]>
Planix, Inc. <[email protected]> Avoncote Farms <[email protected]>
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