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authorLinus Torvalds <torvalds@linux-foundation.org>2017-01-25 00:02:35 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2017-01-25 00:02:35 +0000
commitf7bc4a69dcfb1f03014b95e88b6a468f8cbf2d43 (patch)
tree40a9ed8219fe727f82a2f7879be9977e5434c891
parent8eb1af7ddb0c251f9060e08036cf86ad73114b15 (diff)
pci: test for unexpectedly disabled bridgesv4.10-rc5-mmotm-2017-01-24-15-37
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 a881c0d3d2e8..1b760c1f3300 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1096,6 +1096,15 @@ 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]);