[PATCH 1/2] platform/x86: asus-wmi: keep the lid-flip state when UNKNOWN is set

[Robin Everaars]

On some convertibles the lid-flip devstate sets ASUS_WMI_DSTS_UNKNOWN_BIT
alongside the state bit while the machine is folded. Measured on an ASUS
ProArt PX13 (HN7306EAC), ASUS_WMI_DEVID_LID_FLIP_ROG answers 0x00010000
open and 0x00010003 folded, that is presence | status | UNKNOWN.

asus_wmi_get_devstate_simple() treats that bit as "the state is not known"
and fails the call with -ENODEV, so asus_wmi_tablet_mode_get_state()
discards a perfectly good state sitting in bit 0 and SW_TABLET_MODE never
moves.

Add asus_wmi_tablet_sw_get_state(), which gates on the presence bit only
and returns the status bit. Use it from the two tablet-switch paths. Every
other caller of asus_wmi_get_devstate_simple() is untouched, so the change
is confined to the tablet switch.

Signed-off-by: Robin Everaars <robineveraars@xxxxx>
---
 drivers/platform/x86/asus-wmi.c | 32 ++++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86
/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index 8610663b8..f68fd2bcd 100644
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -706,12 +706,40 @@ static void asus_wmi_tablet_sw_report(struct asus_wmi *asus, bool value)
 	input_sync(asus->inputdev);
 }
 
+/*
+ * Read the lid-flip state directly rather than through
+ * asus_wmi_get_devstate_simple().
+ *
+ * On some convertibles the lid-flip devstate sets ASUS_WMI_DSTS_UNKNOWN_BIT
+ * alongside the state bit while folded. Measured on an ASUS ProArt PX13
+ * (HN7306EAC), devid ASUS_WMI_DEVID_LID_FLIP_ROG answers 0x00010000 open and
+ * 0x00010003 folded, i.e. presence | state | UNKNOWN. The generic helper reads
+ * that bit as "the state is not known" and rejects the whole call with -ENODEV,
+ * so asus_wmi_tablet_mode_get_state() discards a perfectly good state sitting in
+ * bit 0 and the switch never moves. Only presence gates the value here, which is
+ * safe because this path serves 
the tablet switch alone.
+ */
+static int asus_wmi_tablet_sw_get_state(struct asus_wmi *asus, u32 dev_id)
+{
+	u32 retval;
+	int err;
+
+	err = asus_wmi_get_devstate(asus, dev_id, &retval);
+	if (err < 0)
+		return err;
+
+	if (!(retval & ASUS_WMI_DSTS_PRESENCE_BIT))
+		return -ENODEV;
+
+	return !!(retval & ASUS_WMI_DSTS_STATUS_BIT);
+}
+
 static void asus_wmi_tablet_sw_init(struct asus_wmi *asus, u32 dev_id, int event_code)
 {
 	struct device *dev = &asus->platform_device->dev;
 	int result;
 
-	result = asus_wmi_get_devstate_simple(asus, dev_id);
+	result = asus_wmi_tablet_sw_get_state(asus, dev_id);
 	if (result >= 0) {
 		input_set_capability(asus->inputdev, EV_SW, SW_TABLET_MODE);
 		asus_wmi_tablet_sw_report(asus, result);
@@ -786,7 +814,7 @@ static void asus_wmi_tablet_mode_get_state(struct asus_wmi *asus)
 	if (!asus->tablet_switch_dev_id)
 		return;
 
-	result = asus_wmi_get_devstate_simple(asus, asus->tablet_switch_dev_id);
+	result = asus_wmi
_tablet_sw_get_state(asus, asus->tablet_switch_dev_id);
 	if (result >= 0)
 		asus_wmi_tablet_sw_report(asus, result);
 }
-- 
2.55.0

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