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Reverse Engineered 802.11b+ Drivers
orv writes "When Andreas Mohr found that his new wireless networking card wasn't supported under Linux rather than returning the card and getting himself a supported one, he decided to set up a project to write his own drivers instead - http://acx100.sourceforge.net.
Companies such as D-Link had initially promised to release linux drivers for these cards but later backed down from that promise and announced that Linux would not be supported and that customers should not hold on to the cards in the hope of getting them working, as shown on their current FAQ.
Texas Instruments, the makers of the chipsets upon which these 802.11b+ cards are based refused to release code or specifications for the cards, no doubt for similar reasons that were recently discussed here.
The fact that the current alpha release is certainly as good, and in some areas better, than the binary drivers that escaped from one of the card manufactureres speaks volumes for the quality and determination of the team to create their own drivers."
The problem is - some of the unsupported cards using this chipset used to use a different (eg Orinoco or Prism) chipset and have not updated the name of the card so that you think you are buying a supported card (as listed in many howtos) but in fact are getting a newer model with no available linux driver.
-=DaveHowe=-
[uh oh, we did make it to /. after all... ;)]
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Yep, that's a very bad thing indeed.
So bad that we decided to dedicate a major part of the README file to it:
--- AND FINALLY... ---
Let me mention that we REALLY dislike the way very stupid hardware vendors
name their cards containing DIFFERENT chipsets!!
One of these vendors is SpeedStream/Siemens: a card that uses the same
name "SS1021" is available in both Orinoco chip and ACX100 chip versions.
Another one is D-Link: they have "DWL-650" and "DWL-650+".
"DWL-650+" is simply an improved version of the "DWL-650", right?
WRONG!
The standard versions use Prism2.5, whereas the "+" versions use ACX100
chipset. Good luck in finding a (correct) driver!!
And it's even WORSE: I just found out that there is some newer
version of the "DWL-650" out that also contains the ACX100
(it uses the same hardware as the "+" versions).
This BRAINDEAD STUPIDITY in device naming easily entitles D-Link
for the "Most Braindead Hardware Vendor 2003" award. And of course
they were also talking about developing another Linux driver for some time,
without any results (although I guess that's because they wanted to
develop it, but were not allowed to, unfortunately, so it's understandable).
IF you dare to release cards with a different incompatible chipset
that doesn't even have proper driver support for a popular alternative OS,
then AT LEAST change the card name in order to let people know and discern
which hardware to avoid like the plague, for heaven's sake!
This is such a [CENSORED], I could [OUCH, CENSORED!]...
It's one thing to decide to not release Linux drivers and/or specs for a popular chipset (and frankly, we sort of have to respect such a decision, even though it hurts a lot), but it's an ENTIRELY DIFFERENT (and much worse!) thing to release cards with DIFFERENT chipsets using the SAME card name as older, well-supported chipsets.
That's a capital crime which should by punished by revoking any and all hardware development rights and/or licenses of the relevant company
(heck, or maybe I should have removed that smiley after all, since it IS a very infuriating action after all
But I think I should stop now since I already wrote most of that in the README file paragraph pasted above
Anyway, let me also mention that I'm glad how well the development process of our driver is coming along. We are fixing many bugs (and implementing many improvements!) on a daily basis, and the team work is definitely great!
Also, we had several users donate money and/or hardware (access points!) to the main developers,
which is very astonishing to me, but that's not to say that I don't like that
In fact the access point that has been donated to me arrived today
Finally, let's hope that we might even attract proper driver and spec support by Texas Instruments, by showing that a really good driver IS possible.
(admittedly we're still "a bit" far off from a perfect driver, but we're definitely working on it
That's it. Have fun using our driver!
Andreas Mohr
The DMCA isn't just a blanket law covering all instances of reverse engineering, regardless of the context. The DMCA covers reverse engineering in cases where it is being used for copyright circumvention, which driver hackers aren't trying to do. MOST Linux drivers have to be written this way. Don't get me wrong, the DMCA is still a pile of hot garbage. I just hate it when people are scared to do ANYTHING that might be useful because of the DMCA.
Basically most work was done by disassembling a linux binary module for the chipset that leaked from one of the manufacturers.
Additionally the behaviour of the card and correct initialisation process was determined by analysing the ARM disassembly of the firmware and watching the traffic that goes between the access point board and its embedded PCcard.
I didn't see this posted anywhere, but if you read a little more about the topic, you would have found the probable reason for why the manufacturers aren't releasing drivers. It ISN'T some MS scheme to screw linux users. The manufactureres are affraid that releasing drivers will get them in trouble with the US government. Apparantley the card can be reconfigured to transmit on military/police/other "forbidden" frequencies. The manufacturers don't want to have to deal with the repercussions of releasing such a "weapon". Pretty stupid really, considering theres already an effort out there, with some success I hear, at reverse engineering the windoze driver, in order to reconfigure the transmit frequency.