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authorLinus Torvalds <torvalds@linux-foundation.org>2015-09-11 00:03:11 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2015-09-11 00:03:11 +0000
commit844414697361664d00f4663f09463fff092dc9bd (patch)
treebdbb3a151fb1f1e4a0c09096fc70f2bd6271aada
parentacf06fdc95151bdf11606428a06e2836c0f8a351 (diff)
pci: test for unexpectedly disabled bridgesv4.2-mmotm-2015-09-10-16-30
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 6a9a1116f1eb..83e7c0b8c0a0 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1021,6 +1021,15 @@ 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]);