traditional syscalls with DRIVER_MODULE ????
Jim Bryant
kc5vdj.freebsd at gmail.com
Thu May 26 21:28:43 UTC 2011
excuse me while i pull my head out of my posterior...
yup.
it wasn't DRIVER_MODULE() doing it... it was the usb_fifo_attach....
i think i'm back on the right track now... thanks for pointing me in
the right direction.
Hans Petter Selasky wrote:
> Hi,
>
> On Wednesday 25 May 2011 21:02:29 Jim Bryant wrote:
>
>> do start_read/stop_read and start_write/stop_write map directly to the
>> userland read(2) and write(2) calls?
>>
>
> No, but they are called from these calls. The idea is that you use the FIFO
> mechanism already present there when moving data, and poll() will be
> automatically handled. Probably that is not suitable for your purpose?
>
>
>> i had looked at this previously, and am a bit confused on if the above
>> is correct.
>>
>> even if they are the direct interface to read(2)/write(2), the issue of
>> a poll method for select(2) still exists...
>>
>> grepping all DRIVER_MODULE usages comes up with only two poll methods:
>>
>> powerpc/powermac/pmu.c: DEVMETHOD(adb_hb_controller_poll,
>> pmu_poll),
>> powerpc/powermac/cuda.c: DEVMETHOD(adb_hb_controller_poll,
>> cuda_poll),
>>
>> and those are unhelpful.
>>
>>
>
>
>> please excuse me if these are newbie questions, but, i'm still in the
>> learning process.
>>
>
> It is OK to ask questions :-)
>
>
>> i can do this if there is a way to prevent DRIVER_MODULE from creating
>> the devfs nodes, and instead do this in a hybrid way using DRIVER_MODULE
>> and make_dev(9), which has the exact traditional functionality i want in
>> this. any ideas?
>>
>
> Why can't you create the node when you receive a device_attach event?
>
>
>> two of the three device nodes this driver will create
>> will require read(2)/select(2) interfaces visible to userland, and the
>> third driver will require write(2) visible to userland.
>>
>
>
>> the question is: is there a way to use DRIVER_MODULE, which seems
>> necessary for usbdi, yet create the devfs nodes using make_dev/cdevsw?
>> i would prefer to not have DRIVER_MODULE create the device nodes.
>>
>
> DRIVER_MODULE() only will create devices if you have a load function which
> does so. It is only called once!
>
> --HPS
>
>
More information about the freebsd-drivers
mailing list