lkml.org 
[lkml]   [2024]   [Apr]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v1] ACPI: scan: Avoid enumerating devices with clearly invalid _STA values
On Fri, 26 Apr 2024 18:56:21 +0200
"Rafael J. Wysocki" <rjw@rjwysocki.net> wrote:

> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> 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/88179311a503493099028c12ca37d430@huawei.com/
> Suggested-by: Salil Mehta <salil.mehta@huawei.com>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Seems a sensible tidying up. Hopefully nothing was relying on
this looser behavior. One trivial thing inline.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> ---
> 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 enabled bit as
> + * well to avoid attempting to use the device.
> + */

Comment seems to be in a slightly odd place. Perhaps one line earlier makes
more sense? Or was the intent to mention functional here?

> + 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,
>
>
>


\
 
 \ /
  Last update: 2024-04-29 10:30    [W:0.079 / U:0.640 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site