From: Oliver Neukum <oneukum@suse.com>
Date: Wed, 11 Feb 2026 18:11:04 +0000 (+0100)
Subject: media: rc: ttusbir: respect DMA coherency rules
X-Git-Tag: v7.1-rc1~169^2~132
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=50acaad3d202c064779db8dc3d010007347f59c7;p=thirdparty%2Fkernel%2Flinux.git

media: rc: ttusbir: respect DMA coherency rules

Buffers must not share a cache line with other data structures.
Allocate separately.

Fixes: 0938069fa0897 ("[media] rc: Add support for the TechnoTrend USB IR Receiver")
Cc: stable@vger.kernel.org
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
---

diff --git a/drivers/media/rc/ttusbir.c b/drivers/media/rc/ttusbir.c
index a2a64a860264b..3848ad3a6b85f 100644
--- a/drivers/media/rc/ttusbir.c
+++ b/drivers/media/rc/ttusbir.c
@@ -32,7 +32,7 @@ struct ttusbir {
 
 	struct led_classdev led;
 	struct urb *bulk_urb;
-	uint8_t bulk_buffer[5];
+	u8 *bulk_buffer;
 	int bulk_out_endp, iso_in_endp;
 	bool led_on, is_led_on;
 	atomic_t led_complete;
@@ -186,13 +186,16 @@ static int ttusbir_probe(struct usb_interface *intf,
 	struct rc_dev *rc;
 	int i, j, ret;
 	int altsetting = -1;
+	u8 *buffer;
 
 	tt = kzalloc_obj(*tt);
+	buffer = kzalloc(5, GFP_KERNEL);
 	rc = rc_allocate_device(RC_DRIVER_IR_RAW);
-	if (!tt || !rc) {
+	if (!tt || !rc || buffer) {
 		ret = -ENOMEM;
 		goto out;
 	}
+	tt->bulk_buffer = buffer;
 
 	/* find the correct alt setting */
 	for (i = 0; i < intf->num_altsetting && altsetting == -1; i++) {
@@ -281,8 +284,8 @@ static int ttusbir_probe(struct usb_interface *intf,
 	tt->bulk_buffer[3] = 0x01;
 
 	usb_fill_bulk_urb(tt->bulk_urb, tt->udev, usb_sndbulkpipe(tt->udev,
-		tt->bulk_out_endp), tt->bulk_buffer, sizeof(tt->bulk_buffer),
-						ttusbir_bulk_complete, tt);
+			  tt->bulk_out_endp), tt->bulk_buffer, 5,
+			  ttusbir_bulk_complete, tt);
 
 	tt->led.name = "ttusbir:green:power";
 	tt->led.default_trigger = "rc-feedback";
@@ -350,6 +353,7 @@ out:
 		kfree(tt);
 	}
 	rc_free_device(rc);
+	kfree(buffer);
 
 	return ret;
 }
@@ -373,6 +377,7 @@ static void ttusbir_disconnect(struct usb_interface *intf)
 	usb_kill_urb(tt->bulk_urb);
 	usb_free_urb(tt->bulk_urb);
 	rc_free_device(tt->rc);
+	kfree(tt->bulk_buffer);
 	usb_set_intfdata(intf, NULL);
 	kfree(tt);
 }