summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2018-05-18 00:05:10 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2018-05-18 00:05:10 +0000
commit7400fc6942aefa2e009272d0e118284f110c5088 (patch)
tree7f7220de5411b76f36dab58a496714e7a787d16d
parentdce19576e5d644a63ffd293dccfb863e931ff131 (diff)
pci: test for unexpectedly disabled bridgesv4.17-rc5-mmotm-2018-05-17-16-26
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 dbfe7c4f3776..9f087286d24c 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1099,6 +1099,15 @@ 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]);