Messages in this thread | | | Date | Sun, 23 Dec 2012 17:46:07 +0100 | Subject | [v3.8-rc1] Multimedia regression, ioctl(17,..)-API changed ? | From | Jörg Otte <> |
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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@ideasonboard.com> [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
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