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authorLinus Torvalds <torvalds@linux-foundation.org>2018-01-13 01:12:59 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2018-01-13 01:12:59 +0000
commit464fe39f7861587939207607b0ab57539768dd07 (patch)
tree2a36b4ffb7a8c414a50f8b645bfa8a06e2ad8639
parentb033f40250082a93de196bd9ab2ee71ce634d78a (diff)
pci: test for unexpectedly disabled bridgesv4.15-rc7-mmotm-2018-01-12-16-53
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 764ca7b8840d..6957aaa70f6b 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1094,6 +1094,15 @@ 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]);