On Tue, 2005-01-25 at 01:39, Eric W. Biederman wrote: > Len Brown <[EMAIL PROTECTED]> writes: > > > On Wed, 2005-01-19 at 02:31, Eric W. Biederman wrote: > > > When coming out of apic mode attempt to set the appropriate > > > apic back into virtual wire mode. This improves on previous > versions > > > of this patch by by never setting bot the local apic and the > ioapic > > > into veritual wire mode. > > > > > > This code looks at data from the mptable to see if an ioapic has > > > an ExtInt input to make this decision. A future improvement > > > is to figure out which apic or ioapic was in virtual wire mode > > > at boot time and to remember it. That is potentially a more > accurate > > > method, of selecting which apic to place in virutal wire mode. > > > > > > > The call to find_isa_irq_pin() will always fail on ACPI-enabled > systems, > > so this patch is a NO-OP unless the system is booted in MPS mode. > > > > Do we really want to be adding this complexity for obsolete systems? > > Are there systems that fail without this patch? > > Yes there are bleeding edge systems that fail without this patch. > And I have them. That is why I wrote the code.
What bleeding edge system support MPS and does not support ACPI? > I do agree that find_isa_irq_pin is a suboptimal way to get this > information, looking at the ioapics at boot time would be better. > However it works for me, the code is not wrong, and as you said > usually the code becomes a noop. > > If I can find the appropriate place in the boot path to examine > the ioapics before they get stomped I am more than willing to write > code that will handle this even in the presence of acpi data. I belive we don't touch the IO_APICS in either MPS or ACPI mode before setup_IO_APIC. > In addition this code is not a complete noop because when > find_isa_irq_pin fails it does put the local apic in virtual wire > mode. If the goal of this patch is to restore the hardware to the state that it was before Linux scribbed on it, then it might be a better ideal to save/restore the actual register values the BIOS gave us rather than writing hard-coded values, no? -Len - 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/
