Felix Radensky wrote:
Hello Kenji-san,
Kenji Kaneshige wrote:
Felix Radensky wrote:
Hello Kenji-san,
Kenji Kaneshige wrote:
I'm not sure, but I guess pci_setup_bridge() didn't update IO
base/limit
and Mem base/limit of the bridge (0000:00:02.0) because of the
following
lines.
static void pci_setup_bridge(struct pci_bus *bus)
{
struct pci_dev *bridge = bus->self;
struct resource *res;
struct pci_bus_region region;
u32 l, bu, lu, io_upper16;
if (pci_is_enabled(bridge))
<===============================
return; <===============================
dev_info(&bridge->dev, "PCI bridge to [bus %02x-%02x]\n",
bus->secondary, bus->subordinate);
...
It seems the bridge was already enabled by
pci_assign_unassigned_resources()
at boot time. Does removing those lines make any change?
Yes, with these lines removed bridge memory window is properly
allocated.
These lines are to prevent updating IO or memory windows when there are
some devices working behind the bridge. So please note that removing
these lines is just for debugging.
For some reason bridge memory is disabled, but if I enable it via
setpci, and
also enable device memory, then everything works fine. If the system
is booted
when device behind the bridge is plugged in, bridge memory is enabled.
Maybe because of the following lines, I guess.
void pci_enable_bridges(struct pci_bus *bus)
{
struct pci_dev *dev;
int retval;
list_for_each_entry(dev, &bus->devices, bus_list) {
if (dev->subordinate) {
if (!pci_is_enabled(dev)) { <=======
retval = pci_enable_device(dev);<=======
pci_set_master(dev); <=======
}
...
Yes, but removing this check is not enough. The bridge is enabled after
first scan, but it's
memory is disabled. So simply calling pci_enable_device() will not
help, it will return without
enabling memory. I had to call pci_disable_device() before
pci_enable_device() to make things
work.
One possible cause is that pcibios_enable_device() for the bridge didn't
return any error even though it didn't work properly (ex. cannot access
to the command register, and so on) on your platform when there is no
device behind the bridge. But it is just my guess.
Should pcibios_enable_device() return an error if it fails to enable
bridge memory ?
I think the device is expected to be ready to work if pci_enable_device()
returns without error. So I think pci_enable_device() should return an
error if it fails to enable the device (device is not ready to work). In
this case, detecting your bridge's failure seems PPC specific to me. So I
thought pcibios_enable_device() was the right to return an error. If
pcibios_enable_device() returned an error, pci_dev->enable_cnt would
decremented by pci_enable_device() (like pci_disable_device() does) and
this problem would not happen.
On the other hand, as Ben suggested, handling this by specific hot-plug
driver would be one of the other candidate to fix the problem.
Thanks,
Kenji Kaneshige
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
