Input: synaptics-rmi4 - only read the F54 query registers which are used

aduggan-syna · dtor · commit 9768935264c4 · 2017-06-23T00:08:48.000-07:00
The F54 driver is currently only using the first 6 bytes of F54 so there is no need to read all 27 bytes. Some Dell systems (Dell XP13 9333 and similar) have an issue with the touchpad or I2C bus when reading reports larger then 16 bytes. Reads larger then 16 bytes are reported in two HID reports. Something about the back to back reports seems to cause the next read to report incorrect data. This results in F30 failing to load and the click button failing to work. Previous issues with the I2C controller or touchpad were addressed in: commit 5b65c2a ("HID: rmi: check sanity of the incoming report") Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=195949 Signed-off-by: Andrew Duggan <aduggan@synaptics.com> Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> Reviewed-by: Nick Dyer <nick@shmanahar.org> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
diff --git a/drivers/input/rmi4/rmi_f54.c b/drivers/input/rmi4/rmi_f54.c
@@ -31,9 +31,6 @@
 #define F54_GET_REPORT          1
 #define F54_FORCE_CAL           2
 
-/* Fixed sizes of reports */
-#define F54_QUERY_LEN			27
-
 /* F54 capabilities */
 #define F54_CAP_BASELINE	(1 << 2)
 #define F54_CAP_IMAGE8		(1 << 3)
@@ -95,7 +92,6 @@ struct rmi_f54_reports {
 struct f54_data {
 	struct rmi_function *fn;
 
-	u8 qry[F54_QUERY_LEN];
 	u8 num_rx_electrodes;
 	u8 num_tx_electrodes;
 	u8 capabilities;
@@ -632,22 +628,23 @@ static int rmi_f54_detect(struct rmi_function *fn)
 {
 	int error;
 	struct f54_data *f54;
+	u8 buf[6];
 
 	f54 = dev_get_drvdata(&fn->dev);
 
 	error = rmi_read_block(fn->rmi_dev, fn->fd.query_base_addr,
-			       &f54->qry, sizeof(f54->qry));
+			       buf, sizeof(buf));
 	if (error) {
 		dev_err(&fn->dev, "%s: Failed to query F54 properties\n",
 			__func__);
 		return error;
 	}
 
-	f54->num_rx_electrodes = f54->qry[0];
-	f54->num_tx_electrodes = f54->qry[1];
-	f54->capabilities = f54->qry[2];
-	f54->clock_rate = f54->qry[3] | (f54->qry[4] << 8);
-	f54->family = f54->qry[5];
+	f54->num_rx_electrodes = buf[0];
+	f54->num_tx_electrodes = buf[1];
+	f54->capabilities = buf[2];
+	f54->clock_rate = buf[3] | (buf[4] << 8);
+	f54->family = buf[5];
 
 	rmi_dbg(RMI_DEBUG_FN, &fn->dev, "F54 num_rx_electrodes: %d\n",
 		f54->num_rx_electrodes);
