diff mbox series

[2/3] HID: pidff: Make sure to fetch pool before checking SIMULTANEOUS_MAX

Message ID 20250208173628.5734-3-tomasz.pakula.oficjalny@gmail.com
State New
Headers show
Series HID: pidff: Compatibility update and new devices | expand

Commit Message

Tomasz Pakuła Feb. 8, 2025, 5:36 p.m. UTC
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 | 34 ++++++++++++++++------------------
 1 file changed, 16 insertions(+), 18 deletions(-)
diff mbox series

Patch

diff --git a/drivers/hid/usbhid/hid-pidff.c b/drivers/hid/usbhid/hid-pidff.c
index f23381b6e344..acdcc0af86ba 100644
--- a/drivers/hid/usbhid/hid-pidff.c
+++ b/drivers/hid/usbhid/hid-pidff.c
@@ -604,28 +604,26 @@  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 = 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);
-
-		/* 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;
-		}
+	int i;
+	struct hid_device *hid = pidff->hid;
+
+	/* Try 20 times if PID_SIMULTANEOUS_MAX < 2.
+	   We must make sure this isn't just an error */
+	for(i = 0; i < 20; i++) {
+		hid_hw_request(hid, pidff->reports[PID_POOL], HID_REQ_GET_REPORT);
+		hid_hw_wait(hid);
+
+		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]);
 }
 
 /*