linux-kernel - [PATCH 4.19 25/72] platform/x86: intel-vbtn: Stop reporting SW

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Date:   Mon, 29 Mar 2021 09:58:01 +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, Hans de Goede <hdegoede@...hat.com>
Subject: [PATCH 4.19 25/72] platform/x86: intel-vbtn: Stop reporting SW_DOCK events

From: Hans de Goede <hdegoede@...hat.com>

commit 538d2dd0b9920334e6596977a664e9e7bac73703 upstream.

Stop reporting SW_DOCK events because this breaks suspend-on-lid-close.

SW_DOCK should only be reported for docking stations, but all the DSDTs in
my DSDT collection which use the intel-vbtn code, always seem to use this
for 2-in-1s / convertibles and set SW_DOCK=1 when in laptop-mode (in tandem
with setting SW_TABLET_MODE=0).

This causes userspace to think the laptop is docked to a port-replicator
and to disable suspend-on-lid-close, which is undesirable.

Map the dock events to KEY_IGNORE to avoid this broken SW_DOCK reporting.

Note this may theoretically cause us to stop reporting SW_DOCK on some
device where the 0xCA and 0xCB intel-vbtn events are actually used for
reporting docking to a classic docking-station / port-replicator but
I'm not aware of any such devices.

Also the most important thing is that we only report SW_DOCK when it
reliably reports being docked to a classic docking-station without any
false positives, which clearly is not the case here. If there is a
chance of reporting false positives then it is better to not report
SW_DOCK at all.

Cc: stable@...r.kernel.org
Signed-off-by: Hans de Goede <hdegoede@...hat.com>
Link: https://lore.kernel.org/r/20210321163513.72328-1-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/platform/x86/intel-vbtn.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

--- a/drivers/platform/x86/intel-vbtn.c
+++ b/drivers/platform/x86/intel-vbtn.c
@@ -46,8 +46,16 @@ static const struct key_entry intel_vbtn
 };

 static const struct key_entry intel_vbtn_switchmap[] = {
-	{ KE_SW,     0xCA, { .sw = { SW_DOCK, 1 } } },		/* Docked */
-	{ KE_SW,     0xCB, { .sw = { SW_DOCK, 0 } } },		/* Undocked */
+	/*
+	 * SW_DOCK should only be reported for docking stations, but DSDTs using the
+	 * intel-vbtn code, always seem to use this for 2-in-1s / convertibles and set
+	 * SW_DOCK=1 when in laptop-mode (in tandem with setting SW_TABLET_MODE=0).
+	 * This causes userspace to think the laptop is docked to a port-replicator
+	 * and to disable suspend-on-lid-close, which is undesirable.
+	 * Map the dock events to KEY_IGNORE to avoid this broken SW_DOCK reporting.
+	 */
+	{ KE_IGNORE, 0xCA, { .sw = { SW_DOCK, 1 } } },		/* Docked */
+	{ KE_IGNORE, 0xCB, { .sw = { SW_DOCK, 0 } } },		/* Undocked */
 	{ KE_SW,     0xCC, { .sw = { SW_TABLET_MODE, 1 } } },	/* Tablet */
 	{ KE_SW,     0xCD, { .sw = { SW_TABLET_MODE, 0 } } },	/* Laptop */
 };