Messages in this thread | | | Subject | Re: Please!! Help me to help us to use WinModems in Linux | Date | Fri, 09 Apr 1999 13:31:30 -0700 | From | bwoodard@cisco ... |
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C'mon here we should be a bit more encouraging. Sure using the hardware will suck rocks and chew up your CPU cycles but to be quite honest quite, making even a lame driver available would be useful to the linux community.
Quite a few of us are shackled with a useless WinModem through no fault of our own. I bought a laptop; it has a WinModem built in, I have to carry a PCMCIA card when I go on the road. The CPU loading is not a problem for me, the laptop has a PII/300 in it that hardly ever breaks a sweat. I expect that I am not the only one in this boat.
I personally have never written a driver for anything but Solaris but the requirements seem pretty modest. It is just that the code paths in the interrupt handlers might be a bit long. My CPU would probably be happy to chew on something for a while, even kernel compiles don't seem to take very long anymore.
Richard,
I would reccomend getting a copy of:
Linux Device Drivers by Alessandro Rubini, O'Reilly and Asscociates ISBN 1-56592-292-1 http://www.amazon.com/exec/obidos/ASIN/1565922921/ref=sim_books/002-7777075-8168254
and
Linux Kernel Internals 2nd edition by M. Beck et al. Addison-Wesley ISBN 201331438 http://www.amazon.com/exec/obidos/ASIN/0201331438/qid=923689511/sr=1-1/002-7777075-8168254
> On Thu, 8 Apr 1999, Richard Reynolds wrote: > > someone saying that this modem was all software driven (duh I knew that) and > > that the drivers were somekind of seceret (did not know that can't even see > > how, sence i found them?) and that they were not available. Well as of now i > > have the technology (drivers source code) to make the drivers required to > > run my modem. I can recreate the drivers for windozs make new ones for DOS > > (also not "supported" by the vendor) but i have no ability to program in > > Linux and don't even know where to start. The drivers would need to do 3 > > major things > I've heard that the timing was very important to these kinds of modem > trying to support these brain-dead things would mess up scheduling as it > needs constant real-time dsp in order to work. > IMHO well-behaved hardware should use buffering, dma, etc to be time > constraint friendly to the OS. Real modems are serial ports buffered with > 16550A's or better. Or maybe USB modems as I've been rumored as to their > existence. > > 1. initialize the device maybee at a very early stage the ports are turned > > off until initialize is complete and successful. > > 2. process every 32bit word before being sent to the modem. > > 3. process every 32bit word after being recieved by the modem. > Play dsp cause the manufactorer was to cheap to be good? > Chew up 20% or more of your cpu? Constantly allow it to preempt the things > running on your system? > Sounds real ugly to me. > Of course I'll be quiet now as I'm a little extreme in the fact that I > would pay extra for a modem without the evil fax capabilities. > I really hate fax;-> > > Please read the FAQ at http://www.tux.org/lkml/
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