hello, I am Kernel Kosh (think. military :)
I would like to know, has anyone actually been able to try a USB ACM
compatible modem ? cause I have up to now, been unable to find one, since
they are mostly Win98, I would like to try, if you can give me a suggestion.
Thanks you guys, keep up the good work
Kernel Kosh
>From: Paul Mackerras <paulus@linuxcare.com>
>To: Jamie Lokier <lu@tantalophile.demon.co.uk>, Alan Cox
><alan@lxorguk.ukuu.org.uk>
>CC: Andi Kleen <ak@suse.de>, linux-kernel@vger.rutgers.edu,
>linux-usb@suse.com, Vojtech Pavlik <vojtech@suse.cz>, Al Longyear
><longyear@pobox.com>
>Subject: Re: Irq context wrong for USB ACM serial driver calling PPP?
>Date: Thu, 9 Mar 2000 11:01:46 +1100
>
>On Tue, 07 Mar 2000, Jamie Lokier wrote:
>
> > The problem with USB ACM is that it queues the data from its irq
> > handler, and calls the line discipline's write_wakeup from irq context.
> > The standard PC serial driver calls write_wakeup from BH context.
> >
> > PPP's write_wakeup then does some complicated stuff which isn't quite
> > irq safe, but could probably be made so.
>
>The PPP driver's write_wakeup routine will typically want to do things
>like compressing the next packet and sending it out. We could do this
>at hw interrupt level but it would be very undesirable because it would
>mean there was a relatively long time when the serial interrupts were
>disabled.
>
>If the PPP driver had to cope with the write_wakeup being called from hw
>interrupt context, it would be necessary for the PPP driver to have code
>to schedule a bottom half (or tasklet or whatever) so it could do the
>transmit-side processing at BH level.
>
>This code is already in all the other serial drivers in the kernel. I
>would be loath to put it into the PPP driver just to cope with the USB ACM
>driver.
>
>I guess ultimately it's a question of whether the code goes in all of the
>serial drivers or alternatively in all of the line disciplines. At the
>moment it is in the serial drivers. Ultimately it could probably be
>pulled out into a serial driver support library of some kind.
>
>Paul.
>
>--
>Paul Mackerras, Senior Open Source Researcher, Linuxcare, Inc.
>+61 2 6262 8990 tel, +61 2 6262 8991 fax
>paulus@linuxcare.com.au, http://www.linuxcare.com.au/
>Linuxcare. Support for the revolution.
>
>-
>To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>the body of a message to majordomo@vger.rutgers.edu
>Please read the FAQ at http://www.tux.org/lkml/
______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Wed Mar 15 2000 - 21:00:16 EST