On Sat, Mar 10, 2012 at 12:00 AM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
> It will rediscover removed pci root buses.
>
> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
> ---
> drivers/pci/pci-sysfs.c | 2 ++
> 1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index 4d122cb..fc0a7de 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -284,6 +284,7 @@ msi_bus_store(struct device *dev, struct device_attribute *attr,
>
> #ifdef CONFIG_HOTPLUG
> static DEFINE_MUTEX(pci_remove_rescan_mutex);
> +void __weak arch_pci_root_rescan(void) { }
> static ssize_t bus_rescan_store(struct bus_type *bus, const char *buf,
> size_t count)
> {
> @@ -295,6 +296,7 @@ static ssize_t bus_rescan_store(struct bus_type *bus, const char *buf,
>
> if (val) {
> mutex_lock(&pci_remove_rescan_mutex);
> + arch_pci_root_rescan();
> while ((b = pci_find_next_bus(b)) != NULL)
> pci_rescan_bus(b);
> mutex_unlock(&pci_remove_rescan_mutex);
This is gross. We used to rescan every previously-discovered PCI root bus.
Now, we do the same, plus:
1) Scan the ACPI namespace for PCI host bridges, adding and scanning
any we haven't seen before, and
2) scan domain 0, buses 0 - pcibios_last_bus, looking for any we
haven't seen before.
These just don't fit with the previous functionality. The scan should
be done on the *ACPI namespace*, which is where any new bridges would
live. It shouldn't be done in the PCI namespace. The new bridges
aren't part of PCI.
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