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authorLinus Torvalds <torvalds@linux-foundation.org>2015-01-30 01:03:01 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2015-01-30 01:03:01 +0000
commit69e3ee778e7168cf0fa603da0aab2ea746dfdd14 (patch)
tree21348fe12e5db818b85569c81f9b39a5aefcc7d1
parentc12b56813e69edbddcfd385a662df1fcd7cfd896 (diff)
pci: test for unexpectedly disabled bridgesv3.19-rc6-mmotm-2015-01-29-16-39
The all-ones value is not just a "device didn't exist" case, it's also potentially a quite valid value, so not restoring it would be wrong. What *would* be interesting is to hear where the bad values came from in the first place. It sounds like the device state is saved after the PCI bus controller in front of the device has been crapped on, resulting in the PCI config cycles never reaching the device at all. Something along this patch (together with suspend/resume debugging output) migth help pinpoint it. But it really sounds like something totally brokenly turned off the PCI bridge (some ACPI shutdown crud? I wouldn't be entirely surprised) Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--drivers/pci/pci.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 81f06e8dcc04..b20adfd6a305 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1006,6 +1006,15 @@ static void pci_restore_pcix_state(struct pci_dev *dev)
int pci_save_state(struct pci_dev *dev)
{
int i;
+ u32 val;
+
+ /* Unable to read PCI device/manufacturer state? Something is seriously wrong! */
+ if (pci_read_config_dword(dev, 0, &val) || val == 0xffffffff) {
+ printk("Broken read from PCI device %s\n", pci_name(dev));
+ WARN_ON(1);
+ return -1;
+ }
+
/* XXX: 100% dword access ok here? */
for (i = 0; i < 16; i++)
pci_read_config_dword(dev, i * 4, &dev->saved_config_space[i]);