[SeaBIOS] [RFC PATCH v3 3/3] fw/pci: Allocate IGD stolen memory
kevin at koconnor.net
Mon Feb 15 15:15:09 CET 2016
On Sat, Feb 13, 2016 at 06:03:31PM -0700, Alex Williamson wrote:
> On Sat, 13 Feb 2016 19:20:32 -0500
> "Kevin O'Connor" <kevin at koconnor.net> wrote:
> > This confuses me - why didn't the host system BIOS turn on the LCD
> > panel during host bootup?
> It turns off when we reset the device between VM instances or between
> VM boots. IGD supports Function Level Reset (FLR).
> > >Another desktop IvyBridge system
> > > doesn't really care about the vBIOS so long as we don't ask it to
> > > output anything before the guest native drivers are loaded. If we
> > > could, I think we'd just enable vBIOS for laptop panel support, but
> > > that's really not an option, it's going to run as a boot option ROM as
> > > well, so we need to fix the issues that it generates there.
> > From my experience with coreboot, running the vga option rom multiple
> > times during a given boot is very fragile. (By multiple times, I mean
> > either the host running it and then a guest, or running it multiple
> > times from multiple guests.) YMMV.
> We do this regularly for graphics assignment, Nvidia, AMD, and now
> Intel. It generally works ok. Perhaps you've seen issues with the
> option ROM being run multiple times without resetting the device. I
> could certainly believe that.
Interesting. Using the FLR could be useful on some coreboot systems
where users want to run the option rom twice. Thanks.
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