On Wed, 2011-05-04 at 00:51 +0200, Sebastian Herbszt wrote: > Glauber Costa wrote: > > 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. > > This might not always be the desired case. How can i control which card wins?
Bus enumeration order, only. But that's a good question. Maybe we should come up with a method other than bus enumeration for that. But at the tip of my tongue, none come to mind. > > And this is totally orthogonal to whether it is loaded as a pci device, > > or in vgaroms/ > > The statement is true for both methods. > > Shouldn't VGAbdf be set to the last (the winning) card then? That's certainly better, you are right. > > > 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
