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authorLinus Torvalds <torvalds@linux-foundation.org>2018-01-19 01:08:30 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2018-01-19 01:08:30 +0000
commitd67adaa0dd2b533559485b9e22da21b344d1508c (patch)
tree0ef8a3a8bda75421bdfedc85237639b8010c0838
parentc20ad84f48c6a8b31ed9ff2c991732cf339a4799 (diff)
pci: test for unexpectedly disabled bridgesv4.15-rc8-mmotm-2018-01-18-16-31
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]);