On Fri, Apr 07, 2023 at 10:54:00PM +0200, Helge Deller wrote: > On 4/6/23 15:21, Thomas Zimmermann wrote: > > From: Daniel Vetter <daniel.vetter@xxxxxxxx> > > > > Since vgaarb has been promoted to be a core piece of the pci subsystem > > we don't have to open code random guesses anymore, we actually know > > this in a platform agnostic way, and there's no need for an x86 > > specific hack. See also commit 1d38fe6ee6a8 ("PCI/VGA: Move vgaarb to > > drivers/pci") > > > > This should not result in any functional change, and the non-x86 > > multi-gpu pci systems are probably rare enough to not matter (I don't > > know of any tbh). But it's a nice cleanup, so let's do it. > > > > There's been a few questions on previous iterations on dri-devel and > > irc: > > > > - fb_is_primary_device() seems to be yet another implementation of > > this theme, and at least on x86 it checks for both > > vga_default_device OR rom shadowing. There shouldn't ever be a case > > where rom shadowing gives any additional hints about the boot vga > > device, but if there is then the default vga selection in vgaarb > > should probably be fixed. And not special-case checks replicated all > > over. > > > > - Thomas also brought up that on most !x86 systems > > fb_is_primary_device() returns 0, except on sparc/parisc. But these > > 2 special cases are about platform specific devices and not pci, so > > shouldn't have any interactions. > > Nearly all graphics cards on parisc machines are actually PCI cards, > but the way we handle the handover to graphics mode with STIcore doesn't > conflicts with your planned aperture changes. > So no problem as far as I can see for parisc... Ah I thought sticore was some very special bus, if those can be pci cards underneath then I guess some cleanup eventually might be a good idea? For anything with a pci bus it's rather strange when vgaarb and fb_is_primary_device() aren't a match ... -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch