Hi Jörg, Em Sun, 23 Dec 2012 17:46:07 +0100 Jörg Otte <jrg.otte@xxxxxxxxx> escreveu: > 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. Do you have any other non-uvc device to test? > 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) This ioctl returns -ENOTTY already with other media drivers on v3.7. > ioctl(17, VIDIOC_QUERYCTRL, 0x7fff6cce66f0) = -1 EINVAL (Invalid argument) This change is new, and, AFAIKT, only UVC returns -ENOENT on 3.8-rc1. This is likely the source of the troubles. > > 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) Yeah, it started an endless loop here, likely because kde4 seems to be expecting either 0 or -EINVAL error code for VIDIOC_QUERYCTRL. It should be noticed that there are other valid error codes here. For example, if this ioctl is not implemented, -ENOTTY may also be returned. Fortunately, almost all drivers do implement this ioctl. The expected return error codes for this ioctl are described at: http://linuxtv.org/downloads/v4l-dvb-apis/vidioc-queryctrl.html In practice, except for the uvc driver, the current return codes are EINVAL/EACCES/ENOTTY. > . > 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. Rafael made a patch fixing it, and Linus should be applying it. Regards, Mauro -- 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
