Re: Linux Incompatibility List

[Gianni Tedesco]

On Sat, 2004-08-28 at 21:42 -0400, Andrew Miklas wrote:
> (Sorry for the long delay...)

Thats OK.

> Yeah, we tried that at first too (actually, we were using Frank Cornelis'  
> patches to Bochs).  The problem with dumping all the PCI activity (even while 
> the interface isn't sending/receiving) is that there is a huge amount of data 
> to sift through.  Even capturing for just a for a few seconds generates 
> megabytes of data.  You also have to deal with various events (like the 
> watchdog timer) going off at random times and getting mixed in with the 
> send/receive data.  We also found DMA a little tricky too (ie. you need to 
> dump out any data that the chip will bus-master to itself to see how it is 
> structured).

OK, exactly which drivers were you using to do this? When I had the
interface brought up in win2k-server with the bcmwl5.sys driver I was
seeing every few hundred milliseconds a batch of say 12 2-byte reads on
the register space to check status...

> Also, we figured it would cause problems for supporting the whole range of 
> devices that can be handled by the wl.o drivers.  For example, from looking 
> at the module, we can see that the driver will have somewhat different 
> behaviour according to exactly what MAC and radio chips are present, the 
> interface being used (ie. PCI, cardbus, etc.), the vendor, model number, and 
> revision of the board itself, the contents of the ROM, etc.  We decided that 
> there was simply too many combinations to make the data capture approach 
> useful over the entire range of Broadcom hardware, unless you repeat the 
> process on every variation.

Hrm, you're sure those variations aren't trivial? Although theres lots
of checks, I would have thought they would just be stuff like "card A
supports X, Y and Z features"?

The approach that makes the most sense to me is get 1 card working to
the point where it sends/receives packets, then look at the binaries to
see what the variations are, and how they apply to what cards and just
go fill in the blanks...

> > Anyway, perhaps once I've had some time to make a little more progress
> > we would be able to compare some notes?
> 
> Sure, let me know when you're ready.

I just need to improve logging support in my pciproxy patch and setup a
2nd machine with a working wireless card, then I can start in earnest.

Also, you mention DMA and sending/receiving packets, exactly how much
progress have you made so far?

-- 
// Gianni Tedesco (gianni at scaramanga dot co dot uk)
lynx --source www.scaramanga.co.uk/scaramanga.asc | gpg --import
8646BE7D: 6D9F 2287 870E A2C9 8F60 3A3C 91B5 7669 8646 BE7D

Attachment: signature.asc
Description: This is a digitally signed message part