If get_pbus() is called for a device which has no parent/ancestor bus
with nonzero PCI bus operations, get_pbus() will get stuck in a silent
endless loop.
Detect the endless loop and break out with an error message.
Such a situation can happen if the device tree is not yet
initialized/walked completely.
This fixes the unexplainable hang if pci_{read,write}_config{8,16,32}was
used in early mainboard code for the AMD DBM690T. Instead, the code will
now die() with a meaningful error message.
Thanks to Ward Vandewege for testing my patches to track down that bug.
Signed-off-by: Carl-Daniel Hailfinger <[email protected]>
Index: LinuxBIOSv2-asus_m2a-vm/src/devices/pci_ops.c
===================================================================
--- LinuxBIOSv2-asus_m2a-vm/src/devices/pci_ops.c (Revision 3967)
+++ LinuxBIOSv2-asus_m2a-vm/src/devices/pci_ops.c (Arbeitskopie)
@@ -28,6 +28,12 @@
{
struct bus *pbus = dev->bus;
while(pbus && pbus->dev && !ops_pci_bus(pbus)) {
+ if (pbus == pbus->dev->bus) {
+ printk_alert("%s in endless loop looking for a parent "
+ "bus with ops_pci_bus for %s, breaking out\n",
+ __func__, dev_path(dev));
+ break;
+ }
pbus = pbus->dev->bus;
}
if (!pbus || !pbus->dev || !pbus->dev->ops ||
!pbus->dev->ops->ops_pci_bus) {
--
http://www.hailfinger.org/
Index: LinuxBIOSv2-asus_m2a-vm/src/devices/pci_ops.c
===================================================================
--- LinuxBIOSv2-asus_m2a-vm/src/devices/pci_ops.c (Revision 3967)
+++ LinuxBIOSv2-asus_m2a-vm/src/devices/pci_ops.c (Arbeitskopie)
@@ -28,6 +28,12 @@
{
struct bus *pbus = dev->bus;
while(pbus && pbus->dev && !ops_pci_bus(pbus)) {
+ if (pbus == pbus->dev->bus) {
+ printk_alert("%s in endless loop looking for a parent "
+ "bus with ops_pci_bus for %s, breaking out\n",
+ __func__, dev_path(dev));
+ break;
+ }
pbus = pbus->dev->bus;
}
if (!pbus || !pbus->dev || !pbus->dev->ops ||
!pbus->dev->ops->ops_pci_bus) {
--
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