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authorLinus Torvalds <torvalds@linux-foundation.org>2019-07-04 23:05:37 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2019-07-04 23:05:37 +0000
commit4cfa05acb2325535f9b0731b3e95658a2f2b32d4 (patch)
tree28c6ab249498c39b7afb01c173c7ae98c88fe5cb
parent5dbda1db5c18067677d9f4c6bfda6279c8a9a2da (diff)
pci: test for unexpectedly disabled bridgesv5.2-rc7-mmotm-2019-07-04-15-01
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]);