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authorLinus Torvalds <torvalds@linux-foundation.org>2017-12-13 01:11:58 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2017-12-13 01:11:58 +0000
commit80a0c4df565dd0a964873abd018a0ce48a7fb673 (patch)
tree0e6c8aaad4d7b1c6bcf724be2a3c8cf56f3175fe
parentcdbeaff092794561a6b67fb7be4e9ef0367332eb (diff)
pci: test for unexpectedly disabled bridgesv4.15-rc3-mmotm-2017-12-12-16-32
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 4a7c6864fdf4..caa849d0a9ac 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1094,6 +1094,15 @@ 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]);