[SeaBIOS] VM won't start since 76e58028d28e78431f9de3cee0b3c88d807fa39d

Laszlo Ersek lersek at redhat.com
Mon Mar 18 09:43:35 CET 2013

On 03/18/13 09:24, Michael S. Tsirkin wrote:
> On Sun, Mar 17, 2013 at 10:19:45PM -0400, Kevin O'Connor wrote:
>> On Sun, Mar 17, 2013 at 08:27:36PM +0200, Michael S. Tsirkin wrote:
>>> With seabios built from source, and latest qemu, VMs hang during boot
>>> for me.  Bisect points at this commit:
>>> 76e58028d28e78431f9de3cee0b3c88d807fa39d
>>> Reverting this helps. Guest is stuck quite late, after
>>> 'switching root' message, so this could be just an OS
>>> visible change that it can't handle.
>>> Didn't try debugging more yet.
>> What OS didn't boot?
>> -Kevin
> Sorry. It's a rhel6 image.

Apologies for not trying this myself, but I can't very easily do it
today. If you have everything handy, could you try booting with
pci=nocrs on the guest kernel cmdline? If it boots, can you compare

                    without     with 76e58028
                    76e58028    but also pci=nocrs

guest dmesg

acpidump & iasl -d
the DSDT and SSDT

I suspect that the "late" hang (ie. after switching root) occurs when
the efifb driver (or some such...) tries to use the window(s) retrieved
from ACPI. Parsing itself should happen much earlier.

Again, sorry for not doing this myself!


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