git: ad9cc3f1da14 - main - uvideo: limit isochronous transfers to 32 frames

The branch main has been updated by adrian:

URL: https://cgit.FreeBSD.org/src/commit/?id=ad9cc3f1da14da168e676aeadecd77dfaff6fc06

commit ad9cc3f1da14da168e676aeadecd77dfaff6fc06
Author:     Abdelkader Boudih <[email protected]>
AuthorDate: 2026-08-09 16:58:55 +0000
Commit:     Adrian Chadd <[email protected]>
CommitDate: 2026-08-09 16:59:01 +0000

    uvideo: limit isochronous transfers to 32 frames
    
    Raising UVIDEO_NFRAMES_MAX from 40 to 128 in 3b6f833c95eb improved
    throughput on xhci but made every camera on an ehci bus fail to
    stream. Integrated webcams became unusable.
    
    Measured on a MacBookPro9,2 with two ehci(4) FaceTime HD cameras and an
    xhci(4) Logitech C920:
    
                              128            32
      ehci, 12 captures       0 ok           12 ok
      xhci 1920x1080          5 fps           5 fps
      xhci 1280x720          10 fps          10 fps
    
    Fixes:          3b6f833c95eb
    
    Reviewed by:    bapt
    Differential Revision:  https://reviews.freebsd.org/D58501
---
 sys/dev/usb/video/uvideo.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sys/dev/usb/video/uvideo.h b/sys/dev/usb/video/uvideo.h
index fbcc0b2ec930..512cf7ac8316 100644
--- a/sys/dev/usb/video/uvideo.h
+++ b/sys/dev/usb/video/uvideo.h
@@ -640,7 +640,7 @@ struct usb_video_format_desc {
 /*
  * Driver specific private definitions.
  */
-#define UVIDEO_NFRAMES_MAX	128
+#define UVIDEO_NFRAMES_MAX	32
 
 #define UVIDEO_IXFERS		5
 struct uvideo_vs_iface {