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authorLinus Torvalds <torvalds@linux-foundation.org>2019-06-20 04:12:01 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2019-06-20 04:12:01 +0000
commit7da4e9141274380b1a934e2f3ab60be339730184 (patch)
tree92f92afc0cd6efc05a29b0f30d4555945b5db1d6
parent56ae651d59895c09c348bb0674a91a5e76d6ac8a (diff)
pci: test for unexpectedly disabled bridgesv5.2-rc5-mmotm-2019-06-19-20-32
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 5451b58d8402..b174e6b1baba 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1320,6 +1320,15 @@ 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]);