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authorLinus Torvalds <torvalds@linux-foundation.org>2019-07-17 01:06:19 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2019-07-17 01:06:19 +0000
commite0edcc80d433dc18b6950b889adda434b6a6ab65 (patch)
tree9d191e7123f4170de8955616589100379981dbfc
parent636fd3acb53a7f54443324e155fe1fafe84e8675 (diff)
pci: test for unexpectedly disabled bridgesv5.2-mmotm-2019-07-16-17-14
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 29ed5ec1ac27..64814986a547 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1341,6 +1341,15 @@ static void pci_restore_ltr_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]);