[openfirmware] Troubleshooting VGA under qemu?

[Marcin Cieslak]

On Wed, 30 Sep 2015, James Cameron wrote:

> On Wed, Sep 30, 2015 at 10:04:36AM +0000, Marcin Cieslak wrote:
> > 1) Would that be possible to have a dual-console mode (similar to
> > what FreeBSD early bootloader has) so that both vga and serial
> > console are active? ofw prints messages on the serial console even
> > if disabled, only input is not working.
> > Newer QEMU offers Bochs VGA adapter

> 
> Thanks.  Want me to commit?

Would be good!

> Do you happen to know which version of QEMU switched to Bochs?

No idea. One can switch VGA adapters with -vga switch:

 -vga std  -> Bochs adapter (1234:1111), seems to be the default 
 -vga cirrus ->  Cirrus (1013:00b8), also works
 -vga vmware -> VMWare (15ad:404) - DOES NOT WORK

It seems that FCode gets detected, but the driver
does not want to attach:

Assigning PCI Space of length    10000
Memory Space...
  Base Reg: 2001030  = 11010000 
  Function:15ad  Function: 405
  Non FCode Format ROM Image. 
  Checking for built-in FCode match for 
  Vendor:15ad  Device: 405
  Checking for built-in FCode match... DROPIN NAME MATCH 
PCI PROBE-SELF:  Phys.hi = 1800 

Regarding "silent serial" problem - it occurs when
"serial-console" is not defined and the VGA adapter
does not attach (as it is the case for vmware now):

One gets on the serial console this output:

Install console
Can't open output device.
Generic PC, Serial #0, 32 MiB memory installed

but ofw continues to print to the serial
device as it did before, which is good.

Maybe "Install console" step should still probe
for the input device even if the output is broken?

~Marcin