On Wed, 2011-05-04 at 00:31 +0200, Sebastian Herbszt wrote: > Glauber Costa wrote: > > On Wed, 2011-05-04 at 00:02 +0200, Sebastian Herbszt wrote: > >> Anthony Liguori wrote: > >> > On 05/03/2011 03:23 PM, Sebastian Herbszt wrote: > >> >> Glauber Costa wrote: > >> >>> It is theorectically possible for a system to have more than > >> >>> one pci vga card. In particular, I am interested in the use of SGAbios > >> >>> as a pci device, alongside of a normal vga bios in QEMU. > >> >> > >> >> Can't SGAbios be loaded as an option rom without this change? > >> > > >> > But then you're loading it as a legacy ROM which is fairly ugly and > >> > requires additional SeaBIOS hackery. > >> > >> Why is this ugly and which additional hackery does it need? > >> SGAbios is a legacy ROM; the PNP header is disabled and there is no PCIR. > > > > It is, but does not need to be (I've also patched sgabios to include a > > PCIR). Since it is a device, it is nice to have it plugged it to a bus. > > If for nothing else, for discovering capabilities - A guest using > > sgabios this way is now aware that it has a double-head system. > > I don't think "it is a device", more likely a functionality. SGAbios doesn't > add a new > device/hardware to the system.
This depends on how you model it. One can think that this functionality is achieved by hooking a device into the system. "Hooking a device" is how most functionality is achieved in real systems anyway. > Do you plan to add a new (emulated) PCI device and deploy SGAbios thru its > BAR? Yes > Do you plan to add support for "Google Memory Console"? No. > > > Also, let us not focus only in the specifics: Having two pci vga cards > > is a real possibility, there's even a use case for that, as anthony > > mentioned. > > If you call the init function of two vga roms, will the last one win and hook > int 10h? Yes. And this is totally orthogonal to whether it is loaded as a pci device, or in vgaroms/ The statement is true for both methods. In the specific case of sgabios, it chains the int10h calls to whatever was there before, which is, IMHO, a very sane thing. > Sebastian > _______________________________________________ SeaBIOS mailing list [email protected] http://www.seabios.org/mailman/listinfo/seabios
