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authorMauro Carvalho Chehab <mchehab@osg.samsung.com>2015-06-16 06:26:59 -0300
committerLinus Torvalds <torvalds@linux-foundation.org>2015-06-17 20:53:36 -1000
commit6cea28d01ee834c4437cccab07f3086435de08a4 (patch)
tree310096f8006dcbf4bb42fc5d3c8463c3b6b5e7ed /Documentation/kobject.txt
parent49fe9bcc507fc82fac17c5c1a2ff7f83e5a19c67 (diff)
downloadlinux-6cea28d01ee834c4437cccab07f3086435de08a4.tar.bz2
Kconfig: disable Media Controller for DVB
Since when we start discussions about the usage Media Controller for complex hardware, one thing become clear: the way it is, MC fails to map anything different than capture/output/m2m video-only streaming. The point is that MC has entities named as devnodes, but the only devnode used (before the DVB patches) is MEDIA_ENT_T_DEVNODE_V4L. Due to the way MC got implemented, however, this entity actually doesn't represent the devnode, but the hardware I/O engine that receives data via DMA. By coincidence, such DMA is associated with the V4L device node on webcam hardware, but this is not true even for other V4L2 devices. For example, on USB hardware, the DMA is done via the USB controller. The data passes though a in-kernel filter that strips off the URB headers. Other V4L2 devices like radio may not even have DMA. When it have, the DMA is done via ALSA, and not via the V4L devnode. In other words, MC is broken as a whole, but tagging it as BROKEN right now would do more harm than good. So, instead, let's mark, for now, the DVB part as broken and block all new changes to MC while we fix this mess, whith we hopefully will do for the next Kernel version. Requested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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