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authorLinus Torvalds <torvalds@linux-foundation.org>2016-02-03 02:03:37 +0000
committerJohannes Weiner <hannes@cmpxchg.org>2016-02-03 02:03:37 +0000
commitbf459eb6a0b27814c8107314f664d2ba8b4d2c43 (patch)
treecead37aaf52b66188c847d3b9a396134e1fbd87e
parentb75cf6e9844ca6beccd125a6f4324c8d786d3306 (diff)
pci: test for unexpectedly disabled bridgesv4.5-rc2-mmotm-2016-02-02-17-08
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 602eb4223510..534e62d03c7d 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1050,6 +1050,15 @@ 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]);