Messages in this thread | | | Date | Wed, 13 Feb 2008 23:07:53 -0600 | From | Matt Domsch <> | Subject | Re: [RFC PATCH] PCI: remove initial bios sort of PCI devices on x86 |
| |
On Wed, Feb 13, 2008 at 03:40:29PM -0800, Greg KH wrote: > We currently keep 2 lists of PCI devices in the system, one in the > driver core, and one all on its own. This second list is sorted at boot > time, in "BIOS" order, to try to remain compatible with older kernels > (2.2 and earlier days). There was also a "nosort" option to turn this > sorting off, to remain compatible with even older kernel versions, but > that just ends up being what we have been doing from 2.5 days... > > Unfortunately, the second list of devices is not really ever used to > determine the probing order of PCI devices or drivers[1]. That is done > using the driver core list instead. This change happened back in the > early 2.5 days. > > Relying on BIOS ording for the binding of drivers to specific device > names is problematic for many reasons, and userspace tools like udev > exist to properly name devices in a persistant manner if that is needed, > no reliance on the BIOS is needed. > > Matt Domsch and others at Dell noticed this back in 2006, and added a > boot option to sort the PCI device lists (both of them) in a > breadth-first manner to help remain compatible with the 2.4 order, if > needed for any reason. This option is not going away, as some systems > rely on them. > > This patch removes the sorting of the internal PCI device list in "BIOS" > mode, as it's not needed at all anymore, and hasn't for many years. > I've also removed the PCI flags for this from some other arches that for > some reason defined them, but never used them. > > This should not change the ordering of any drivers or device probing.
Good plan. I'll be glad when the vestigal internal PCI device list is gone too.
Thanks, Matt
-- Matt Domsch Linux Technology Strategist, Dell Office of the CTO linux.dell.com & www.dell.com/linux
| |