On Tuesday, February 11, 2014 12:42:37 PM Mika Westerberg wrote:
> On Mon, Feb 10, 2014 at 11:39:29PM +0100, Rafael J. Wysocki wrote:
> > > _STA() returns 0x0A instead of 0x0F. Could there be something missing in
> > > the ACPI hotplug code that overlooks this and removes the device on
> > > resume?
> >
> > That is possible. Actually even quite likely, but let's wait for the
> > response
> > from Peter.
>
> Here's a hack that should take the 0xa return value into consideration. It
> turned out that this case is even mentioned in the ACPI spec.
Looks reasonable.
Peter, please check if this one makes a difference for you.
> diff --git a/drivers/pci/hotplug/acpiphp_glue.c
> b/drivers/pci/hotplug/acpiphp_glue.c
> index e2a783fdb98f..014381b42d86 100644
> --- a/drivers/pci/hotplug/acpiphp_glue.c
> +++ b/drivers/pci/hotplug/acpiphp_glue.c
> @@ -730,6 +730,17 @@ static unsigned int get_slot_status(struct acpiphp_slot
> *slot)
> return (unsigned int)sta;
> }
>
> +static inline bool device_sta_valid(unsigned long long sta)
> +{
> + /*
> + * ACPI spec says that _STA may return bit 0 clear with bit 8 set
> + * if the device is valid but does not require device driver to be
> + * loaded (chapter 6.3.7).
> + */
> + unsigned mask = ACPI_STA_DEVICE_ENABLED | ACPI_STA_DEVICE_FUNCTIONING;
> + return (sta & mask) == mask;
> +}
> +
> /**
> * trim_stale_devices - remove PCI devices that are not responding.
> * @dev: PCI device to start walking the hierarchy from.
> @@ -745,7 +756,7 @@ static void trim_stale_devices(struct pci_dev *dev)
> unsigned long long sta;
>
> status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
> - alive = (ACPI_SUCCESS(status) && sta == ACPI_STA_ALL)
> + alive = (ACPI_SUCCESS(status) && device_sta_valid(sta))
> || acpiphp_no_hotplug(handle);
> }
> if (!alive) {
> @@ -792,7 +803,7 @@ static void acpiphp_check_bridge(struct acpiphp_bridge
> *bridge)
> mutex_lock(&slot->crit_sect);
> if (slot_no_hotplug(slot)) {
> ; /* do nothing */
> - } else if (get_slot_status(slot) == ACPI_STA_ALL) {
> + } else if (device_sta_valid(get_slot_status(slot))) {
> /* remove stale devices if any */
> list_for_each_entry_safe_reverse(dev, tmp,
> &bus->devices,
> bus_list)
>
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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