With kernel v3.8 all multimedia programs under KDE4 don't work (Kubuntu 12.04). They alltogether ( at least Dragonplayer (Mediaplayer), Knotify4 (system-sound), System-Settings-Multimedia,..) are looping forever producing 100% CPU-usage and must be killed. With kernel 3.7 there are no problems. I compared an strace of Dragonplayer under 3.7 and 3.8 kernels. The main difference of both traces are the following corresponding outputs just before looping in v3.8 begins: v3.7: ioctl(17, VIDIOC_ENUMSTD, 0x7fff6cce66a0) = -1 EINVAL (Invalid argument) ioctl(17, VIDIOC_QUERYCTRL, 0x7fff6cce66f0) = -1 EINVAL (Invalid argument) v3.8: ioctl(17, VIDIOC_ENUMSTD, 0x7fffc3be6990) = -1 ENOTTY (Inappropriate ioctl for device) ioctl(17, VIDIOC_QUERYCTRL, 0x7fffc3be69e0) = -1 ENOENT (No such file or directory) So error number EINVAL was changed to ENOTTY/ENOENT When Dragonplayer under v3.8 comes to ioctl(17, VIDIOC_QUERYCTRL,...) and sees error number ENOENT instead of EINVAL it loops forever producing 100% CPU usage like so: . . ioctl(17, VIDIOC_QUERYCTRL, 0x7fffc3be69e0) = -1 ENOENT (No such file or directory) ioctl(17, VIDIOC_QUERYCTRL, 0x7fffc3be69e0) = -1 ENOENT (No such file or directory) ioctl(17, VIDIOC_QUERYCTRL, 0x7fffc3be69e0) = -1 ENOENT (No such file or directory) ioctl(17, VIDIOC_QUERYCTRL, 0x7fffc3be69e0) = -1 ENOENT (No such file or directory) ioctl(17, VIDIOC_QUERYCTRL, 0x7fffc3be69e0) = -1 ENOENT (No such file or directory) ioctl(17, VIDIOC_QUERYCTRL, 0x7fffc3be69e0) = -1 ENOENT (No such file or directory) ioctl(17, VIDIOC_QUERYCTRL, 0x7fffc3be69e0) = -1 ENOENT (No such file or directory) ioctl(17, VIDIOC_QUERYCTRL, 0x7fffc3be69e0) = -1 ENOENT (No such file or directory) ioctl(17, VIDIOC_QUERYCTRL, 0x7fffc3be69e0) = -1 ENOENT (No such file or directory) ioctl(17, VIDIOC_QUERYCTRL, 0x7fffc3be69e0) = -1 ENOENT (No such file or directory) ioctl(17, VIDIOC_QUERYCTRL, 0x7fffc3be69e0) = -1 ENOENT (No such file or directory) . and so on . For me it looks like that KDE4 multimedia is not aware of the new error numbers. Looking through the commits I found driver uvcvideo producing the changed error numbers. commit f0ed2ce840b3a59b587e8aa398538141a86e9588 Author: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> [media] uvcvideo: Set error_idx properly for extended controls API failures To verify this I built a v3.8-kernel without uvcvideo (USB_VIDEO_CLASS=n) and the problem disappeared! Simply reverting the commit is not an option for me because then I am left with merge conflicts and I don't know how to resolve. Unfortunately without uvcvideo I lost my usb-camera support. -- Jörg Please CC me I'm not subscribed -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
