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authorLinus Torvalds <torvalds@linux-foundation.org>2019-06-26 00:09:44 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2019-06-26 00:09:44 +0000
commitd1f7c86e62021b15c4927379c0e10b4ebad7cdfb (patch)
treee55cbb200591fb8db2ee1ecd6cf6ea304cb6cfc9
parent634f2909e7ef1ba94c5930f707b3e8e5b8888835 (diff)
pci: test for unexpectedly disabled bridgesv5.2-rc6-mmotm-2019-06-25-16-20
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 5451b58d8402..b174e6b1baba 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1320,6 +1320,15 @@ 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]);