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authorLinus Torvalds <torvalds@linux-foundation.org>2019-03-01 01:13:32 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2019-03-01 01:13:32 +0000
commit0e9c5355555e2ac55fb8be5a5769769bdfcde927 (patch)
treea5ab117029e89bcecca9b50189d1d847927401ae
parent039b6bb5c25db02d392df07d568eca18f0ecb2ec (diff)
pci: test for unexpectedly disabled bridgesv5.0-rc8-mmotm-2019-02-28-16-22
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 ae8db8a3d196..cb5804da8aae 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1316,6 +1316,15 @@ static void pci_restore_ltr_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]);