[linux-dvb] [PATCH] Add driver specific module option to choose dvb adapter numbers, second try

[Michael Krufky]

2008/3/29 Janne Grunau <janne-dvb at grunau.be>:
> Hi,
>
>  I resubmit this patch since I still think it is a good idea to the this
>  driver option. There is still no udev recipe to guaranty stable dvb
>  adapter numbers. I've tried to come up with some rules but it's tricky
>  due to the multiple device nodes in a subdirectory. I won't claim that
>  it is impossible to get udev to assign driver or hardware specific
>  stable dvb adapter numbers but I think this patch is easier and more
>  clean than a udev based solution.
>
>  I'll drop this patch if a simple udev solution is found in a reasonable
>  amount of time. But if there is no I would like to see the attached
>  patch merged.
>
>  Quoting myself for a short desciprtion for the patch:
>
>  > V4L drivers have the {radio|vbi|video}_nr module options to allocate
>  > static minor numbers per driver.
>  >
>  > Attached patch adds a similiar mechanism to the dvb subsystem. To
>  > avoid problems with device unplugging and repluging each driver holds
>  > a DVB_MAX_ADAPTER long array of the preffered order of adapter
>  > numbers.
>  >
>  > options dvb-usb-dib0700 adapter_nr=7,6,5,4,3,2,1,0 would result in a
>  > reversed allocation of adapter numbers.
>  >
>  > With adapter_nr=2,5 it tries first to get adapter number 2 and 5. If
>  > both are already in use it will allocate the lowest free adapter
>  > number.

Personally, I would love to see this merged -- I hope that others will
agree with me.

One critique:

videobuf-dvb is more of a central helper module.  I believe that the
module option should live in the callers of videobuf-dvb (such as
cx88-dvb / saa7134-dvb / cx23885-dvb) rather than within the
videobuf-dvb module, itself.  The array can be passed into
videobuf-dvb the same as was done with dvb-usb-dvb.c

Other than that, I think that this feature would be a valuable
addition to the DVB subsystem.

-Mike Krufky