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authorLinus Torvalds <torvalds@linux-foundation.org>2015-08-06 01:02:44 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2015-08-06 01:02:44 +0000
commit7e456521f271ddf5487e61004994f9ab8dac520d (patch)
treecb08c8a4bd1e8c96986810a7e6fede910b72fc47
parent0218a48ba1a5d7f641dc6d32b99579666b7d380a (diff)
pci: test for unexpectedly disabled bridgesv4.2-rc5-mmotm-2015-08-05-17-06
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 0008c950452c..1bfd1c7f8a6a 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1010,6 +1010,15 @@ 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]);