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authorLinus Torvalds <torvalds@linux-foundation.org>2016-04-22 23:03:04 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2016-04-22 23:03:04 +0000
commit6925c2b8397173f62c3765cab7262aad67a781e5 (patch)
treeafc89d585c66c29f0f6081917e74ac3e235b6886
parent78005d1c75481a3c6328e6463e51841dd89c40d0 (diff)
pci: test for unexpectedly disabled bridgesv4.6-rc4-mmotm-2016-04-22-15-49
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 25e0327d4429..2146eb0e0df2 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1049,6 +1049,15 @@ 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]);