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authorLinus Torvalds <torvalds@linux-foundation.org>2015-04-08 00:06:45 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2015-04-08 00:06:45 +0000
commit9d104dd29f530e69fcc96e72bffaf8a4f588ce0b (patch)
tree18cbb059480effacbac2fc0e9f7e6d3729181286
parent0639ef864fcadf914f22ca3507202d5e03371514 (diff)
pci: test for unexpectedly disabled bridgesv4.0-rc7-mmotm-2015-04-07-16-35
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 28df200bc54c..52b24177e01b 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1007,6 +1007,15 @@ 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]);