Messages in this thread | | | Date | Fri, 21 Feb 2003 14:26:37 +0000 (GMT) | From | Steve Parker <> | Subject | Re: Alcatel SpeedTouch USB Modem |
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Thanks for that, Duncan. Lightweight and stable certainly sounds good; I look forward to the project being ready.
Steve
On Fri, 21 Feb 2003, Duncan Sands wrote:
> On Friday 21 February 2003 03:01, Steve Parker wrote: > > I see that the Alcatel kernel-level driver for the Alcatel SpeedTouch USB > > Modem is now included in the 2.5 kernel. > > Hi Steve, that is so, and I am maintaining it. > > > This seems strange, since there seem to have been (in the past, at least) > > a lot of (panic) problems reported with it, and the speedtouch.sf.net (and > > complimentary speedtouchconf.sf.net) are fully capable of running this > > modem in userspace. > > Have these problems been resolved? Is the kernel driver as stable as the > > userspace one? Are there demonstrable perfomance benefits in the kernel > > driver? > > These problems are being resolved. Most of them have already been resolved. > The cvs version for 2.4, which you can find at > > http://www.linux-usb.org/SpeedTouch/ > > is quite stable. In theory it can still crash (due to various micro races), but in > practice it does not. In any case, these micro races will be fixed soon. The > 2.5 version, which is essentially identical to 2.4 cvs, doesn't work very well > in the current 2.5 kernel. I don't know why. I am working on it. > > I have nothing against the user space version, which I used for many moons. > The kernel version is certainly much lighter weight - less CPU, less memory. > Whether this matters for you depends on your machine/needs. My machine > is slow, and I need all the CPU time I can get! > > > I've certainly been using my modem for well over a year with the userspace > > driver (speedtouch.sf.net) with - as at 2.4.18 - an unpatched kernel, and > > no troubles whatsoever. Is there any need for the Alcatel code in the > > kernel when the n_hdlc and ppp configs already cater for this modem, once > > the microcode is loaded? > > The main disadvantages of the kernel mode driver were: > (1) unstable, and very unstable on SMP/preempt boxes > (2) required running the closed source speedmgmt program > (3) required compiling your own kernel > > The driver is in 2.5, and is heading for inclusion in 2.4, so I expect that in the > future most distributions will ship with the speedtch module compiled. Thus > (3) is going away. > > The cvs version of the user space driver contains a patch for modem_run > which enables it to be used with the kernel driver in place of speedmgmt > (use the -k flag). Thus (2) has already gone away. > > As I mentioned, (1) is (almost) dealt with. > > > What is the status of this driver WRT the Alcatel microcode? Last I heard, > > the Alcatel microcode was required by both the Alcatel kernel-level and > > the speedtouch.sf.net drivers. > > That is correct, but you no longer need to upload it using speedmgmt. > There are efforts underway to reverse engineer the microcode, with > some success. The goal of writing our own microcode (ARM processor > by the way) is still far, far away though. > > All the best, > > Duncan. >
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