V4L/DVB (9133): v4l: disconnect kernel number from minor

The v4l core creates four different video devices (video, vbi, radio, vtx)
and each has its own range of minor numbers. However, modern devices keep
increasing the number of devices that they need so a maximum of 64 video
devices will not be enough in the future. In addition this scheme makes
it very hard to add new device types.

This patch disconnects the kernel number allocation (e.g. video0, video1,
etc.) from the actual minor number (just pick the first free minor).

This allows for much more flexibility in the future. However, it does
require the use of udev. For those who cannot use udev a new CONFIG option
was created that changes the allocation scheme back to the old behavior.

Thanks to Greg KH for suggesting this approach during the 2008 LPC.

In addition, several bugs were fixed in the ivtv and cx18 drivers: these
drivers try to allocate specific kernel numbers but that scheme contained
a bug which caused what should have been e.g. video17 to appear as e.g.
video2.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 2 insertions, 10 deletions

diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h
index d129b56e1a9f..a0a6b41c5e09 100644
--- a/include/media/v4l2-dev.h
+++ b/include/media/v4l2-dev.h
@@ -18,20 +18,11 @@
 
 #define VIDEO_MAJOR     81
 
-/* Minor device allocation */
-#define MINOR_VFL_TYPE_GRABBER_MIN   0
-#define MINOR_VFL_TYPE_GRABBER_MAX  63
-#define MINOR_VFL_TYPE_RADIO_MIN    64
-#define MINOR_VFL_TYPE_RADIO_MAX   127
-#define MINOR_VFL_TYPE_VTX_MIN     192
-#define MINOR_VFL_TYPE_VTX_MAX     223
-#define MINOR_VFL_TYPE_VBI_MIN     224
-#define MINOR_VFL_TYPE_VBI_MAX     255
-
 #define VFL_TYPE_GRABBER        0
 #define VFL_TYPE_VBI            1
 #define VFL_TYPE_RADIO          2
 #define VFL_TYPE_VTX            3
+#define VFL_TYPE_MAX            4
 
 struct v4l2_ioctl_callbacks;
 
@@ -56,6 +47,7 @@ struct video_device
         char name[32];
         int vfl_type;
         int minor;
+        u16 num;
         /* attribute to differentiate multiple indices on one physical device */
         int index;