From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Linux ACPI <linux-acpi@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Salil Mehta <salil.mehta@huawei.com>
Subject: Re: [PATCH v1] ACPI: scan: Avoid enumerating devices with clearly invalid _STA values
Date: Mon, 29 Apr 2024 18:07:32 +0200 [thread overview]
Message-ID: <CAJZ5v0h60B=u7qDw1GOU0r=-apE76jCKLLayo8OBd+KYvWqYhA@mail.gmail.com> (raw)
In-Reply-To: <20240429092942.00004c96@Huawei.com>
On Mon, Apr 29, 2024 at 10:29 AM Jonathan Cameron
<Jonathan.Cameron@huawei.com> wrote:
>
> 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>
Thanks!
> > ---
> > 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?
Rui has noticed this already.
I thought "functional" and wrote "enabled". Oh well, I'll send a v2.
> > + 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,
> >
> >
> >
>
>
prev parent reply other threads:[~2024-04-29 16:07 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-26 16:56 [PATCH v1] ACPI: scan: Avoid enumerating devices with clearly invalid _STA values Rafael J. Wysocki
2024-04-28 4:17 ` Zhang, Rui
2024-04-29 16:06 ` Rafael J. Wysocki
2024-04-29 8:29 ` Jonathan Cameron
2024-04-29 16:07 ` Rafael J. Wysocki [this message]
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