This is a note to let you know that I've just added the patch titled

ACPI / bus: Leave modalias empty for devices which are not present

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: acpi-bus-leave-modalias-empty-for-devices-which-are-not-present.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Thu Feb 1 14:00:34 CET 2018

From: Hans de Goede hdegoede@redhat.com Date: Sun, 15 Oct 2017 21:24:49 +0200 Subject: ACPI / bus: Leave modalias empty for devices which are not present

From: Hans de Goede hdegoede@redhat.com

[ Upstream commit 10809bb976648ac58194a629e3d7af99e7400297 ]

Most Bay and Cherry Trail devices use a generic DSDT with all possible peripheral devices present in the DSDT, with their _STA returning 0x00 or 0x0f based on AML variables which describe what is actually present on the board.

Since ACPI device objects with a 0x00 status (not present) still get an entry under /sys/bus/acpi/devices, and those entry had an acpi:PNPID modalias, userspace would end up loading modules for non present hardware.

This commit fixes this by leaving the modalias empty for non present devices. This results in 10 modules less being loaded with a generic distro kernel config on my Cherry Trail test-device (a GPD pocket).

Signed-off-by: Hans de Goede hdegoede@redhat.com Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/acpi/device_sysfs.c | 4 ++++ 1 file changed, 4 insertions(+)

diff --git a/drivers/acpi/device_sysfs.c b/drivers/acpi/device_sysfs.c index 7b2c48fde4e2..201c7ceb7052 100644 --- a/drivers/acpi/device_sysfs.c +++ b/drivers/acpi/device_sysfs.c @@ -146,6 +146,10 @@ static int create_pnp_modalias(struct acpi_device *acpi_dev, char *modalias, int count; struct acpi_hardware_id *id;

+ /* Avoid unnecessarily loading modules for non present devices. */ + if (!acpi_device_is_present(acpi_dev)) + return 0; + /* * Since we skip ACPI_DT_NAMESPACE_HID from the modalias below, 0 should * be returned if ACPI_DT_NAMESPACE_HID is the only ACPI/PNP ID in the