PCI: Disable decoding for BAR sizing only when it was actually enabled
We disable BARs while sizing them so we don't cause conflicts with other
devices (see 253d2e5498 and bbffe43524). But if device decoding is already
disabled before we size the BAR, we don't need to disable it again.
[bhelgaas: changelog, add PCI_COMMAND_DECODING_ENABLE for readability]
Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index cf57fe7..b50386d 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -156,6 +156,8 @@
return flags;
}
+#define PCI_COMMAND_DECODE_ENABLE (PCI_COMMAND_MEMORY | PCI_COMMAND_IO)
+
/**
* pci_read_base - read a PCI BAR
* @dev: the PCI device
@@ -178,8 +180,10 @@
/* No printks while decoding is disabled! */
if (!dev->mmio_always_on) {
pci_read_config_word(dev, PCI_COMMAND, &orig_cmd);
- pci_write_config_word(dev, PCI_COMMAND,
- orig_cmd & ~(PCI_COMMAND_MEMORY | PCI_COMMAND_IO));
+ if (orig_cmd & PCI_COMMAND_DECODE_ENABLE) {
+ pci_write_config_word(dev, PCI_COMMAND,
+ orig_cmd & ~PCI_COMMAND_DECODE_ENABLE);
+ }
}
res->name = pci_name(dev);
@@ -293,7 +297,8 @@
fail:
res->flags = 0;
out:
- if (!dev->mmio_always_on)
+ if (!dev->mmio_always_on &&
+ (orig_cmd & PCI_COMMAND_DECODE_ENABLE))
pci_write_config_word(dev, PCI_COMMAND, orig_cmd);
if (bar_too_big)