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authorLinus Torvalds <torvalds@linux-foundation.org>2017-05-18 22:01:11 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2017-05-18 22:01:11 +0000
commitecfddce33be51ebedf97f1e03d954c14e575afb6 (patch)
tree43a68128e741747a44d6cc21a32c44c921dd6462
parent1c5f35da2895755fcec3e034f67cc5da09ce0851 (diff)
pci: test for unexpectedly disabled bridgesv4.12-rc1-mmotm-2017-05-18-14-18
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 b01bd5bba8e6..dd5e79de5569 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1098,6 +1098,15 @@ 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]);