[coreboot] SeaBIOS, serial output, and grub

Ward Vandewege ward at gnu.org
Thu May 14 05:23:52 CEST 2009


On Wed, May 13, 2009 at 09:07:46PM -0400, Kevin O'Connor wrote:
> On Wed, May 13, 2009 at 10:46:11AM -0400, Ward Vandewege wrote:
> > On Tue, May 12, 2009 at 11:04:07PM -0400, Kevin O'Connor wrote:
> > > This looks to be an issue with SeaBIOS serial port detection.  Can you
> > > retry with the latest seabios git?  Make sure CONFIG_SERIAL is enabled
> > > in SeaBIOS as grub relies on the serial ports being detected by the
> > > bios.
> [...]
> > But - I just tried on both h8dme and m57sli with Seabios head as of today,
> > and the bug appears to be gone! Did you change something?
> 
> Yes - I committed a fix on Tuesday just prior to sending my email.
> 
> On Wed, May 13, 2009 at 04:29:27PM -0400, Ward Vandewege wrote:
> > If CONFIG_DEBUG_SERIAL is set to 1, the bug persists, but sgabios works.
> > Boot log:
> > 
> >   http://ward.vandewege.net/coreboot/seabios/20090513-seabios-serial-debug-grub-serial-slowness.cap
> >   
> > Thoughts?
> 
> The problem is related to this log report:
> 
>  Found 0 serial ports
> 
> SeaBIOS still isn't properly detecting your serial port.  Can you
> apply the patch below, up the debugging level to 6, and retry?

Will try on Friday.

> Also, unless I'm missing something, sgabios does not appear to be
> working.  If it was working, I'd expect to see double characters - one
> report from seabios and one report from sgabios - for example, I have
> a log with:
> 
> B^MBoooott  ffaaiilleedd::  CCoouulldd  nnoott  rreeaadd  ffrroomm  CCDDRROOMM  ((cco
> oddee  00000033))

Right, that's what I was expecting.

> It looks like the problem is related to the log report:
> 
>  Found option rom with bad checksum: loc=0x000cd000 len=3584 sum=76
> 
> which definitely looks wrong.  Can you grab the latest seabios git and
> run "tools/checksum.py < sgabios.bin" and report the results?  I get:
> 
> $ l sgabios.bin
> -rwxr-xr-x 1 kevin 3153 2009-04-29 21:15 sgabios.bin
> $ tools/checksum.py < sgabios.bin
> sum=4ff00
> 
> which is correct (the last two digits are 00).

Huh:

$ v ../payloads/sgabios.bin 
-rwxr-xr-x 1 root src 3169 2009-04-29 13:56 ../payloads/sgabios.bin*
$ tools/checksum.py <../payloads/sgabios.bin 
sum=50b76

This was built on Debian Lenny, 64 bit, gcc-4.3 (Debian 4.3.2-1.1) 4.3.2 I
believe.

Odd it still works when seabios'es serial debug output is disabled.

Thanks,
Ward.

-- 
Ward Vandewege <ward at fsf.org>
Free Software Foundation - Senior Systems Administrator




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