From: Rafael J. Wysocki <[email protected]>
The return value of _STA with the "present" bit unset and the "enabled"
bit set is clearly invalid as per the ACPI specification, Section 6.3.7
"_STA (Device Status)", so make the ACPI device enumeration code
disregard devices with such _STA return values.
Also, because this implies that status.enabled will only be set if
status.present is set too, acpi_device_is_enabled() can be modified
to simply return the value of the former.
Link: https://uefi.org/specs/ACPI/6.5/06_Device_Configuration.html#sta-device-status
Link: https://lore.kernel.org/linux-acpi/[email protected]/
Suggested-by: Salil Mehta <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
Reviewed-by: Jonathan Cameron <[email protected]>
---
v1 -> v2:
* Fix a confusing comment.
* Add R-by from Jonathan (thank you!)
---
drivers/acpi/bus.c | 11 +++++++++++
drivers/acpi/scan.c | 2 +-
2 files changed, 12 insertions(+), 1 deletion(-)
Index: linux-pm/drivers/acpi/bus.c
===================================================================
--- linux-pm.orig/drivers/acpi/bus.c
+++ linux-pm/drivers/acpi/bus.c
@@ -112,6 +112,17 @@ int acpi_bus_get_status(struct acpi_devi
if (ACPI_FAILURE(status))
return -ENODEV;
+ if (!device->status.present && device->status.enabled) {
+ pr_info(FW_BUG "Device [%s] status [%08x]: not present and enabled\n",
+ device->pnp.bus_id, (u32)sta);
+ device->status.enabled = 0;
+ /*
+ * The status is clearly invalid, so clear the functional bit as
+ * well to avoid attempting to use the device.
+ */
+ device->status.functional = 0;
+ }
+
acpi_set_device_status(device, sta);
if (device->status.functional && !device->status.present) {
Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -1962,7 +1962,7 @@ bool acpi_device_is_present(const struct
bool acpi_device_is_enabled(const struct acpi_device *adev)
{
- return adev->status.present && adev->status.enabled;
+ return adev->status.enabled;
}
static bool acpi_scan_handler_matching(struct acpi_scan_handler *handler,
On Tue, Apr 30, 2024 at 06:02:20PM +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <[email protected]>
>
> The return value of _STA with the "present" bit unset and the "enabled"
> bit set is clearly invalid as per the ACPI specification, Section 6.3.7
> "_STA (Device Status)", so make the ACPI device enumeration code
> disregard devices with such _STA return values.
>
> Also, because this implies that status.enabled will only be set if
> status.present is set too, acpi_device_is_enabled() can be modified
> to simply return the value of the former.
>
Nice!
FWIW,
Reviewed-by: Sudeep Holla <[email protected]>
--
Regards,
Sudeep
On 4/30/24 9:02 AM, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <[email protected]>
>
> The return value of _STA with the "present" bit unset and the "enabled"
> bit set is clearly invalid as per the ACPI specification, Section 6.3.7
> "_STA (Device Status)", so make the ACPI device enumeration code
> disregard devices with such _STA return values.
>
> Also, because this implies that status.enabled will only be set if
> status.present is set too, acpi_device_is_enabled() can be modified
> to simply return the value of the former.
>
> Link: https://uefi.org/specs/ACPI/6.5/06_Device_Configuration.html#sta-device-status
> Link: https://lore.kernel.org/linux-acpi/[email protected]/
> Suggested-by: Salil Mehta <[email protected]>
> Signed-off-by: Rafael J. Wysocki <[email protected]>
> Reviewed-by: Jonathan Cameron <[email protected]>
> ---
Reviewed-by: Kuppuswamy Sathyanarayanan <[email protected]>
>
> v1 -> v2:
> * Fix a confusing comment.
> * Add R-by from Jonathan (thank you!)
>
> ---
> drivers/acpi/bus.c | 11 +++++++++++
> drivers/acpi/scan.c | 2 +-
> 2 files changed, 12 insertions(+), 1 deletion(-)
>
> Index: linux-pm/drivers/acpi/bus.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/bus.c
> +++ linux-pm/drivers/acpi/bus.c
> @@ -112,6 +112,17 @@ int acpi_bus_get_status(struct acpi_devi
> if (ACPI_FAILURE(status))
> return -ENODEV;
>
> + if (!device->status.present && device->status.enabled) {
> + pr_info(FW_BUG "Device [%s] status [%08x]: not present and enabled\n",
> + device->pnp.bus_id, (u32)sta);
Nit: Do you think it should be pr_warn ?
> + device->status.enabled = 0;
> + /*
> + * The status is clearly invalid, so clear the functional bit as
> + * well to avoid attempting to use the device.
> + */
> + device->status.functional = 0;
> + }
> +
> acpi_set_device_status(device, sta);
>
> if (device->status.functional && !device->status.present) {
> Index: linux-pm/drivers/acpi/scan.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/scan.c
> +++ linux-pm/drivers/acpi/scan.c
> @@ -1962,7 +1962,7 @@ bool acpi_device_is_present(const struct
>
> bool acpi_device_is_enabled(const struct acpi_device *adev)
> {
> - return adev->status.present && adev->status.enabled;
> + return adev->status.enabled;
> }
>
> static bool acpi_scan_handler_matching(struct acpi_scan_handler *handler,
>
>
>
>
--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer