Re: Wifi driver for h5000 devices

Hi Milan,

On Fri, Mar 28, 2008 at 3:47 PM, Milan Plzik <milan.plzik_at_gmail.com> wrote:
.....
>
> > I would like to get some help (hints at least), to get the driver
> > working. That includes:
> > 1) testing
>
> Count on me:)
>
>
> > 2) tips how to write a decent driver
> > 3) ideas how to manage the power consumption
>
> I have one idea in my mind -- modify at76_usb to register network
> interface regardless of wifi presence, and when opening the device, it
> would also power up the wifi (and similarly disables when closing the
> device). But I have no idea what side-effects could it have.
>
It sounds nice. But .... Thinking this way no h5000 module/extra code
in /arch dir would be needed. So the idea of the driver would have to
be moved to the at76_usb (I guess).
Thing that chats at kernel-discuss (R.I.P.) thought me is that a fix
should not be temporal solution. So what is going to happen once the
at76_usb gets upgraded - would you supply an extra patch? I think that
general idea of "faking" a wifi device is a nice thing, but it should
be done outside at76_usb. I also think that faking that netdevice may
not be the easiest job - you would need to convince the driver that
usb bus exists, although there is no power supplied to it:)

> >
.....
> >
> > I guess the driver should be converted to platform device style. I
> > have spotted a acx wireless drivers as examples (let's say
> > hx4700_acx.c). I also guess that this way it would be possible to get
> > wifi working without loading and unloading the driver - just
> > controlled by userspace. In future it could get included in the main
> > h5400.c file.
>
> Hmm, good idea, will read it too.
>
Ah - I think I was wrong - the acx family just registers the driver
and turns on the wifi after loading the module - it does not give any
ability to control it by the userspace.
> >
> > Power consumption is a bit harder issue - I have seen it pointed as a
> > problem somewhere else by Milan. Once the ipaq goes to sleep the usb
> > needs to be powered off to save power. This results in bringing down
> > the wifi, so once the device is brought back from sleep the wifi0
> > won't be available. So the whole procedure of configuring the network
> > has to be redone.
> > The problem of resetting the GPBDAT should be handled here too.
> > Also in this section - it would be nice to see wifi0 always in the
> > configuration (ifconfig -a), but activate it (read supply power to it)
> > only when it is up. I have not figured out if it is possible or not,
> > yet....
>
> Hmm, I guess I just wrote it few paragraphs above:) But, as you write,
> problem is in state management. In the worst case we will need to store
> device's configuration somewhere and re-configure it after every
> ifconfig wlan0 up
>
How about just restarting the wifi0 ?
> >
> > I attach diffs of the files I modified to show the changes that I have
> > made. I made the diff against files included in r15 of the angstrom
> > kernel version. It is for general information purpose - not ready to
> > apply to cvs. I also attach clear h5400_wifi.c - as for some people it
> > is easier to operate on small, original file that on unreadable diff.
> >
> > I would be more than happy to hear some ideas, comments or bug reports...
>
> I'm going to play with at76_usb driver in very close future (I have
> to:), so I guess after that I can try to do some modifications proposed
> above and see, what happens.
>
>
> >
> >
> > [1] http://bugs.openembedded.net/show_bug.cgi?id=3161
> > [2] http://delta-9-thc.czuby.net/~yans/hh/h5000/
> >
>
> Milan
>
> > _______________________________________________
> > Kernel-bugs mailing list
> > Kernel-bugs_at_handhelds.org
> > https://www.handhelds.org/mailman/listinfo/kernel-bugs
>
>

-- 
Best regards
Michal Panczyk