From: Takashi Iwai <tiwai@suse.de>
Subject: [PATCH] Input: synaptics: retry query upon error
Date: Tue, 18 Jan 2022 17:28:50 +0100
Message-ID: <s5h35llxb25.wl-tiwai@suse.de>
Patch-mainline: Submitted, linux-input ML
References: bsc#1194086

Some recent laptops such as Lenovo ThinkPad T14 AMD Gen 1 show the
errors at querying synaptics attributes.  This results in the driver
falling back to the legacy mode without multi-finger support.  It
happens only intermittently at some boots, and it seems that the same
query command seems working fine after retrying.

This patch implements a retry of synaptics_query_hardware() call when
it fails after some delay as a workaround.

Buglink: https://bugzilla.suse.com/show_bug.cgi?id=1194086
Signed-off-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/input/mouse/synaptics.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
index ffad142801b3..0f23fba4c36e 100644
--- a/drivers/input/mouse/synaptics.c
+++ b/drivers/input/mouse/synaptics.c
@@ -416,7 +416,7 @@ static int synaptics_resolution(struct psmouse *psmouse,
 	return 0;
 }
 
-static int synaptics_query_hardware(struct psmouse *psmouse,
+static int __synaptics_query_hardware(struct psmouse *psmouse,
 				    struct synaptics_device_info *info)
 {
 	int error;
@@ -450,6 +450,21 @@ static int synaptics_query_hardware(struct psmouse *psmouse,
 	return 0;
 }
 
+static int synaptics_query_hardware(struct psmouse *psmouse,
+				    struct synaptics_device_info *info)
+{
+	int err;
+
+	err = __synaptics_query_hardware(psmouse, info);
+	if (err) {
+		psmouse_info(psmouse, "Query error (%d), retrying...\n", err);
+		msleep(100);
+		err = __synaptics_query_hardware(psmouse, info);
+	}
+
+	return err;
+}
+
 #endif /* CONFIG_MOUSE_PS2_SYNAPTICS || CONFIG_MOUSE_PS2_SYNAPTICS_SMBUS */
 
 #ifdef CONFIG_MOUSE_PS2_SYNAPTICS
-- 
2.31.1