From 6cea28d01ee834c4437cccab07f3086435de08a4 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Tue, 16 Jun 2015 06:26:59 -0300 Subject: [PATCH] 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 Signed-off-by: Hans Verkuil Acked-by: Laurent Pinchart Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Linus Torvalds --- drivers/media/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/media/Kconfig b/drivers/media/Kconfig index 3ef0f90..1570992 100644 --- a/drivers/media/Kconfig +++ b/drivers/media/Kconfig @@ -97,6 +97,7 @@ config MEDIA_CONTROLLER config MEDIA_CONTROLLER_DVB bool "Enable Media controller for DVB" depends on MEDIA_CONTROLLER + depends on BROKEN ---help--- Enable the media controller API support for DVB. -- 2.7.4