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authorLinus Torvalds <torvalds@linux-foundation.org>2016-09-01 00:01:02 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2016-09-01 00:01:02 +0000
commit393dfc957233cdd4ddb7a2e590eaa25935670a9e (patch)
treed9934b3f2d5cd89262b09e34a5bf812330206fd0
parent009bdd3ce9dbf06b0fe7e085ff9028a2369b5385 (diff)
pci: test for unexpectedly disabled bridgesv4.8-rc4-mmotm-2016-08-31-16-06
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 aab9d5115a5f..4443f1cfa45e 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1071,6 +1071,15 @@ 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]);