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authorLinus Torvalds <torvalds@linux-foundation.org>2018-02-01 01:10:45 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2018-02-01 01:10:45 +0000
commit74fabc6ace3da9cb4b8727e0a0ec1a272341cb88 (patch)
tree28ff48c61f6b2b04c89d4f6f346f11573333f462
parent2917c8fccc7b8d1bf52812bb2ef60bf839bd66ff (diff)
pci: test for unexpectedly disabled bridgesv4.15-mmotm-2018-01-31-16-51
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 f6a4dd10d9b0..9416c47edc8b 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1095,6 +1095,15 @@ 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]);