PCI legacy resource fix
Since commit 368c73d4f689dae0807d0a2aa74c61fd2b9b075f 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>
diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index ab78e4b..cb4ced3 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -33,11 +33,22 @@
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, ®ion, res);
pr_debug(" got res [%llx:%llx] bus [%lx:%lx] flags %lx for "
@@ -212,6 +223,10 @@
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)