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authorAndy Lutomirski <luto@kernel.org>2016-02-17 12:43:06 -0800
committerDarren Hart (VMware) <dvhart@infradead.org>2017-06-03 12:23:43 -0700
commit5d4be5f2b1f1919ffbf1ca5c9c014692848bafd1 (patch)
treee68248bb555630f99ec3b2b0e9a5f777dc3c754a
parente4f2e3f0ea13cf3424c0f23d01424c68a428333b (diff)
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: Andy 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: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
-rw-r--r--drivers/platform/x86/dell-rbtn.c29
1 files 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 },