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authorLinus Torvalds <torvalds@linux-foundation.org>2019-01-08 01:04:33 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2019-01-08 01:04:33 +0000
commit79406785424ccbfa9583be6ebd86092af29cf8f2 (patch)
treefc3afab49033c3ae1545549d7f4375e010c39d23
parent4c0da776b367a0d632b4bb8274b54da16645558c (diff)
pci: test for unexpectedly disabled bridgesv5.0-rc1-mmotm-2019-01-07-16-46
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 c9d8e3c837de..588d057d82ee 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1278,6 +1278,15 @@ 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]);