[PATCH v4 2/6] HID: pidff: Make sure to fetch pool before checking SIMULTANEOUS_MAX

["Tomasz Pakuła" <tomasz.pakula.oficjalny@gmail.com>]

As noted by Anssi some 20 years ago, pool report is sometimes messed up.
This worked fine on many devices but casued oops on VRS DirectForce PRO.

Here, we're making sure pool report is refetched before trying to access
any of it's fields. While loop was replaced with a for loop + exit
conditions were moved aroud to decrease the possibility of creating an
infinite loop scenario.

Signed-off-by: Tomasz Pakuła <tomasz.pakula.oficjalny@gmail.com>
---
 drivers/hid/usbhid/hid-pidff.c | 29 +++++++++++++----------------
 1 file changed, 13 insertions(+), 16 deletions(-)

diff --git a/drivers/hid/usbhid/hid-pidff.c b/drivers/hid/usbhid/hid-pidff.c
index f23381b6e344..503f643b59ca 100644
--- a/drivers/hid/usbhid/hid-pidff.c
+++ b/drivers/hid/usbhid/hid-pidff.c
@@ -604,28 +604,25 @@ static void pidff_reset(struct pidff_device *pidff)
 }
 
 /*
- * Refetch pool report
+ * Fetch pool report
  */
 static void pidff_fetch_pool(struct pidff_device *pidff)
 {
-	if (!pidff->pool[PID_SIMULTANEOUS_MAX].value)
-		return;
+	int i;
+	struct hid_device *hid = pidff->hid;
 
-	int i = 0;
-	while (pidff->pool[PID_SIMULTANEOUS_MAX].value[0] < 2) {
-		hid_dbg(pidff->hid, "pid_pool requested again\n");
-		hid_hw_request(pidff->hid, pidff->reports[PID_POOL],
-				HID_REQ_GET_REPORT);
-		hid_hw_wait(pidff->hid);
+	/* Repeat if PID_SIMULTANEOUS_MAX < 2 to make sure it's correct */
+	for(i = 0; i < 20; i++) {
+		hid_hw_request(hid, pidff->reports[PID_POOL], HID_REQ_GET_REPORT);
+		hid_hw_wait(hid);
 
-		/* break after 20 tries with SIMULTANEOUS_MAX < 2 */
-		if (i++ > 20) {
-			hid_warn(pidff->hid,
-				 "device reports %d simultaneous effects\n",
-				 pidff->pool[PID_SIMULTANEOUS_MAX].value[0]);
-			break;
-		}
+		if (!pidff->pool[PID_SIMULTANEOUS_MAX].value)
+			return;
+		if (pidff->pool[PID_SIMULTANEOUS_MAX].value[0] >= 2)
+			return;
 	}
+	hid_warn(hid, "device reports %d simultaneous effects\n",
+		 pidff->pool[PID_SIMULTANEOUS_MAX].value[0]);
 }
 
 /*
-- 
2.48.1