git: 694923501f56 - main - snd_uaudio: Read the UAC2 sample rate back after setting it

The branch main has been updated by christos:

URL: https://cgit.FreeBSD.org/src/commit/?id=694923501f56a5d4519f548ee06db603f9486bc7

commit 694923501f56a5d4519f548ee06db603f9486bc7
Author:     Christos Margiolis <christos@FreeBSD.org>
AuthorDate: 2026-09-15 12:12:43 +0000
Commit:     Christos Margiolis <christos@FreeBSD.org>
CommitDate: 2026-09-15 12:12:43 +0000

    snd_uaudio: Read the UAC2 sample rate back after setting it
    
    Some devices only apply a new sample rate once it has been read back,
    and produce no sound at all otherwise.
    
    PR:             294803
    Reported by:    tatsuki_makino@hotmail.com
    Tested by:      tatsuki_makino@hotmail.com
    MFC after:      2 weeks
    Sponsored by:   The FreeBSD Foundation
    Reviewed by:    emaste
    Differential Revision:  https://reviews.freebsd.org/D59616
---
 sys/dev/sound/usb/uaudio.c | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/sys/dev/sound/usb/uaudio.c b/sys/dev/sound/usb/uaudio.c
index de2b9c467835..491827c87f84 100644
--- a/sys/dev/sound/usb/uaudio.c
+++ b/sys/dev/sound/usb/uaudio.c
@@ -5446,6 +5446,7 @@ uaudio20_set_speed(struct usb_device *udev, uint8_t iface_no,
     uint8_t clockid, uint32_t speed)
 {
 	struct usb_device_request req;
+	usb_error_t err;
 	uDWord data;
 
 	DPRINTFN(6, "ifaceno=%d clockid=%d speed=%u\n",
@@ -5458,7 +5459,27 @@ uaudio20_set_speed(struct usb_device *udev, uint8_t iface_no,
 	USETW(req.wLength, sizeof(data));
 	USETDW(data, speed);
 
-	return (usbd_do_request(udev, NULL, &req, data));
+	err = usbd_do_request(udev, NULL, &req, data);
+	if (err != USB_ERR_NORMAL_COMPLETION)
+		return (err);
+
+	/*
+	 * Read the rate back, because some devices only apply it once it has
+	 * been read, and produce no sound otherwise.
+	 */
+	req.bmRequestType = UT_READ_CLASS_INTERFACE;
+	USETDW(data, 0);
+
+	err = usbd_do_request(udev, NULL, &req, data);
+	if (err != USB_ERR_NORMAL_COMPLETION) {
+		DPRINTF("could not read sample rate back: %s\n",
+		    usbd_errstr(err));
+	} else if (UGETDW(data) != speed) {
+		DPRINTF("sample rate is %u Hz, expected %u Hz\n",
+		    UGETDW(data), speed);
+	}
+
+	return (USB_ERR_NORMAL_COMPLETION);
 }
 
 static int