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authorLinus Torvalds <torvalds@linux-foundation.org>2017-06-02 22:01:52 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2017-06-02 22:01:52 +0000
commit5c84fce56580d5297cd473b57f893e362b332109 (patch)
treea3cd1ba5d8adb1e586a6b9e6677be8b0592e5367
parentc37e2e68abe14437553b3b2a4283f65b5fe26d31 (diff)
pci: test for unexpectedly disabled bridgesv4.12-rc3-mmotm-2017-06-02-14-13
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 2f6f6380fa1c..20faf86f2358 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1098,6 +1098,15 @@ 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]);