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authorLinus Torvalds <torvalds@linux-foundation.org>2014-12-16 02:01:53 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2014-12-16 02:01:53 +0000
commit2e30272045c1463912c42c5c22b2c6656ebc6a76 (patch)
tree8549f8ed51936b780edae5ecc2016c309d84dc49
parenta282b17dd13d6d5aaffac0294f8cd5c29f54291f (diff)
pci: test for unexpectedly disabled bridgesv3.18-mmotm-2014-12-15-17-05
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 cab05f31223f..b3790ec0bc35 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -999,6 +999,15 @@ 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]);