From 5d4be5f2b1f1919ffbf1ca5c9c014692848bafd1 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Wed, 17 Feb 2016 12:43:06 -0800 Subject: [PATCH] platform/x86: dell-rbtn: Improve explanation about DELLABC6 MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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: Andy Lutomirski [dvhart: New commit message and minor comment wording fixes] Cc: Mario Limonciello Cc: "Pali Rohár" Reviewed-by: Andy Shevchenko Signed-off-by: Darren Hart (VMware) --- drivers/platform/x86/dell-rbtn.c | 29 ++++++++++++++++++++--------- 1 file changed, 20 insertions(+), 9 deletions(-) diff --git a/drivers/platform/x86/dell-rbtn.c b/drivers/platform/x86/dell-rbtn.c index dcd9f40a4b18..f5c53ea87158 100644 --- a/drivers/platform/x86/dell-rbtn.c +++ b/drivers/platform/x86/dell-rbtn.c @@ -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 }, -- 2.39.5