Re: [PATCH 0/6] Support calling functions on dedicated physical cpu

From: Peter Zijlstra
Date: Fri Mar 11 2016 - 08:19:34 EST


On Fri, Mar 11, 2016 at 01:15:04PM +0000, One Thousand Gnomes wrote:
> On Fri, 11 Mar 2016 13:25:14 +0100
> Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> > On Fri, Mar 11, 2016 at 12:59:28PM +0100, Juergen Gross wrote:
> > > Some hardware (e.g. Dell Studio laptops) require special functions to
> > > be called on physical cpu 0 in order to avoid occasional hangs. When
> > > running as dom0 under Xen this could be achieved only via special boot
> > > parameters (vcpu pinning) limiting the hypervisor in it's scheduling
> > > decisions.
> >
> > So instead of telling Dell to get their act together and fix their damn
> > firmware, we're going to add the most horrid gunk to the kernel? How
> > does that make sense?
>
> It's been normal forever. The convention with a lot of older BIOS crap
> was always that it should be called on the boot CPU (APM. PnPBIOS etc).
>
> It's a stretch pre-EFI to even call it a "bug"

Yeah, I knew about the APM/PnP muck, but I was under the impression this
was about new hardware.