Commit 5d4be5f2 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Darren Hart (VMware)
Browse files

platform/x86: dell-rbtn: Improve explanation about DELLABC6 



According to Mario at Dell, the DELLABC6 device should not be used on a
Linux system. It also conflicts with Intel-HID and its interactions with
Network Manager. Document that we are aware of the device, but that we
are intentionally ignoring it.

Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
[dvhart: New commit message and minor comment wording fixes]
Cc: Mario Limonciello <mario_limonciello@dell.com>
Cc: "Pali Rohár" <pali.rohar@gmail.com>
Reviewed-by: default avatarAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: default avatarDarren Hart (VMware) <dvhart@infradead.org>
parent e4f2e3f0

drivers/platform/x86/dell-rbtn.c

+20 −9
Original line number Diff line number Diff line
@@ -221,16 +221,27 @@ static const struct acpi_device_id rbtn_ids[] = { 


	/*

	 * This driver can also handle the "DELLABC6" device that

	 * appears on the XPS 13 9350, but that device is disabled

	 * by the DSDT unless booted with acpi_osi="!Windows 2012"

	 * acpi_osi="!Windows 2013".  Even if we boot that and bind

	 * the driver, we seem to have inconsistent behavior in

	 * which NetworkManager can get out of sync with the rfkill

	 * state.

	 * appears on the XPS 13 9350, but that device is disabled by

	 * the DSDT unless booted with acpi_osi="!Windows 2012"

	 * acpi_osi="!Windows 2013".

	 *

	 * On the XPS 13 9350 and similar laptops, we're not supposed to

	 * use DELLABC6 at all.  Instead, we handle the rfkill button

	 * via the intel-hid driver.

	 * According to Mario at Dell:

	 *

	 *  DELLABC6 is a custom interface that was created solely to

	 *  have airplane mode support for Windows 7.  For Windows 10

	 *  the proper interface is to use that which is handled by

	 *  intel-hid. A OEM airplane mode driver is not used.

	 *

	 *  Since the kernel doesn't identify as Windows 7 it would be

	 *  incorrect to do attempt to use that interface.

	 *

	 * Even if we override _OSI and bind to DELLABC6, we end up with

	 * inconsistent behavior in which userspace can get out of sync

	 * with the rfkill state as it conflicts with events from

	 * intel-hid.

	 *

	 * The upshot is that it is better to just ignore DELLABC6

	 * devices.

	 */



	{ "", 0 },

CRA Git | Maintained and supported by SUSTech CRA and CCSE