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authorLinus Torvalds <torvalds@linux-foundation.org>2017-03-17 23:02:55 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2017-03-17 23:02:55 +0000
commit2e20e9e0315e42cc12d2667212996a03bc545589 (patch)
tree4c2188c81bd23f73322a8614fa2adbcdc97d7be8
parent9e3c3f2b76242a4560113387a121e5e2aec6417f (diff)
pci: test for unexpectedly disabled bridgesv4.11-rc2-mmotm-2017-03-17-15-26
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 7904d02ffdb9..8838191dc478 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1096,6 +1096,15 @@ 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]);