On Wed, 2005-03-09 at 00:58 -0500, Jon Smirl wrote: > On Wed, 09 Mar 2005 16:37:13 +1100, Benjamin Herrenschmidt > <[EMAIL PROTECTED]> wrote: > > On Tue, 2005-03-08 at 23:35 -0500, Jon Smirl wrote: > > > This is from /linux-2.5/Documentation/filesystems/sysfs-pci.txt. It > > > describes how ia64 is achieving legacy IO. The VGA control code > > > probably needs to be coordinated with this. > > > > This is a different thing, and I will implement it on ppc one of these > > days. This is for issuing the IO cycles on the bus. It has nothing > > to do with the actual arbitration work. > > Each one of these legacy spaces corresponds to an allowable > simultaneous VGA use. There should be one arbiter per legacy space.
Ugh ? They are or they are not independant, that's a platform thing and has nothing to do with arbitration. They aren't VGA specific neither. The arbitrer uses the vga_conflicts() callback for that purpose. It is defined to always return 1 by default, but the platform can override it if it has separate PCI domains, in order to tell the arbitrer wether 2 cards can conflict or not. Based on that, the arbitrer will, or will not, let you lock the VGA legacy resources simultaneously. Ben. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
