linux-kernel - [PATCH 4.9 44/94] Revert "ACPI / button: Change default behavior to lid_init

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Message-Id: <20170605153104.966288499@linuxfoundation.org>
Date:   Mon,  5 Jun 2017 18:17:20 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Benjamin Tissoires <benjamin.tissoires@...hat.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Subject: [PATCH 4.9 44/94] Revert "ACPI / button: Change default behavior to lid_init_state=open"

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Benjamin Tissoires <benjamin.tissoires@...hat.com>

commit 878d8db039daac0938238e9a40a5bd6e50ee3c9b upstream.

Revert commit 77e9a4aa9de1 (ACPI / button: Change default behavior to
lid_init_state=open) which changed the kernel's behavior on laptops
that boot with closed lids and expect the lid switch state to be
reported accurately by the kernel.

If you boot or resume your laptop with the lid closed on a docking
station while using an external monitor connected to it, both internal
and external displays will light on, while only the external should.

There is a design choice in gdm to only provide the greeter on the
internal display when lit on, so users only see a gray area on the
external monitor. Also, the cursor will not show up as it's by
default on the internal display too.

To "fix" that, users have to open the laptop once and close it once
again to sync the state of the switch with the hardware state.

Even if the "method" operation mode implementation can be buggy on
some platforms, the "open" choice is worse.  It breaks docking
stations basically and there is no way to have a user-space hwdb to
fix that.

On the contrary, it's rather easy in user-space to have a hwdb
with the problematic platforms. Then,  libinput (1.7.0+) can fix
the state of the lid switch for us: you need to set the udev
property LIBINPUT_ATTR_LID_SWITCH_RELIABILITY to 'write_open'.

When libinput detects internal keyboard events, it will overwrite the
state of the switch to open, making it reliable again.  Given that
logind only checks the lid switch value after a timeout, we can
assume the user will use the internal keyboard before this timeout
expires.

For example, such a hwdb entry is:

libinput:name:*Lid Switch*:dmi:*svnMicrosoftCorporation:pnSurface3:*
 LIBINPUT_ATTR_LID_SWITCH_RELIABILITY=write_open

Link: https://bugzilla.gnome.org/show_bug.cgi?id=782380
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@...hat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/acpi/button.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/acpi/button.c
+++ b/drivers/acpi/button.c
@@ -113,7 +113,7 @@ struct acpi_button {

 static BLOCKING_NOTIFIER_HEAD(acpi_lid_notifier);
 static struct acpi_device *lid_device;
-static u8 lid_init_state = ACPI_BUTTON_LID_INIT_OPEN;
+static u8 lid_init_state = ACPI_BUTTON_LID_INIT_METHOD;

 static unsigned long lid_report_interval __read_mostly = 500;
 module_param(lid_report_interval, ulong, 0644);