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authorLinus Torvalds <torvalds@linux-foundation.org>2017-07-07 00:06:54 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2017-07-07 00:06:54 +0000
commit636a65bc6d2d6199ef266ba186b5e3b191484aa4 (patch)
tree20329bde722c8bc49639822f0daa49ef2aaee6ed
parent9c9738ff5b177e4c1df9854ff06c5f7278c8facc (diff)
pci: test for unexpectedly disabled bridgesv4.12-mmotm-2017-07-06-16-18
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 d88edf5c563b..a6f6b9cbb76f 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1092,6 +1092,15 @@ 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]);