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authorLinus Torvalds <torvalds@linux-foundation.org>2014-11-27 00:03:16 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2014-11-27 00:03:16 +0000
commita2d887dee78e23dc092ff14ae2ad22592437a328 (patch)
tree049a5e71527441e6952277fe1a60d053aa8b10b8
parent733d4580fc58e579af6d080f9ab76c2db5338bfa (diff)
pci: test for unexpectedly disabled bridgesv3.18-rc6-mmotm-2014-11-26-15-45
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 a7ac72639c52..d22736818807 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -999,6 +999,15 @@ 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]);