PCI legacy resource fix

Since commit 368c73d4f6 the kernel will try
to update the non-writeable BAR registers 0..3 of PIIX4 IDE adapters if
pci_assign_unassigned_resources() is used to do full resource assignment of
the bus.  This fails because in the PIIX4 these BAR registers have
implicitly assumed values and read back as zero; it used to work because
the kernel used to just write zero to that register the read back value did
match what was written.

The fix is a new resource flag IORESOURCE_PCI_FIXED used to mark a resource
as non-movable.  This will also be useful to keep other import system
resources from being moved around - for example system consoles on PCI
busses.

[akpm@osdl.org: cleanup]
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Ralf Baechle 2006-12-19 13:12:08 -08:00 committed by Greg Kroah-Hartman
parent 7e7a43c32a
commit fb0f2b40fa
3 changed files with 27 additions and 6 deletions

View file

@ -33,11 +33,22 @@ pci_update_resource(struct pci_dev *dev, struct resource *res, int resno)
u32 new, check, mask;
int reg;
/* Ignore resources for unimplemented BARs and unused resource slots
for 64 bit BARs. */
/*
* Ignore resources for unimplemented BARs and unused resource slots
* for 64 bit BARs.
*/
if (!res->flags)
return;
/*
* Ignore non-moveable resources. This might be legacy resources for
* which no functional BAR register exists or another important
* system resource we should better not move around in system address
* space.
*/
if (res->flags & IORESOURCE_PCI_FIXED)
return;
pcibios_resource_to_bus(dev, &region, res);
pr_debug(" got res [%llx:%llx] bus [%lx:%lx] flags %lx for "
@ -212,6 +223,10 @@ pdev_sort_resources(struct pci_dev *dev, struct resource_list *head)
resource_size_t r_align;
r = &dev->resource[i];
if (r->flags & IORESOURCE_PCI_FIXED)
continue;
r_align = r->end - r->start;
if (!(r->flags) || r->parent)