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authorLinus Torvalds <torvalds@linux-foundation.org>2016-07-12 23:03:16 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2016-07-12 23:03:16 +0000
commit8a9c90ec9db88b1a624ea98fa92c8d41aad1584f (patch)
treef4bc8bccdc36df1385745e3f06ed6586e2398cb9
parentccf51b5d4c376e1683ce9bfa1913e486853c08dd (diff)
pci: test for unexpectedly disabled bridgesv4.7-rc7-mmotm-2016-07-12-15-56
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 ba1545aadcb0..583388395629 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1067,6 +1067,15 @@ 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]);