Subject: Re: [linux-audio-dev] Linux Driver for Creamware Luna II
From: Paul Davis (pbd_AT_Op.Net)
Date: Thu Nov 08 2001 - 19:38:10 EET
>> you cannot write a device driver for the Creamware h/w. it requires
>> information that Creamware are not willing to provide. because the
>> card has memory mapped registers, you cannot easily reverse engineer
>> it - there are no io instructions to trace, for example.
>
>What is with using a system debugger like Soft Ice,
>doesn't that show all bits sent within the communication
>between the driver and the soundcard?
foo *p = some_address;
p = 0xfeedface;
no debugger can trace this operation without a lot of extra
information. there is nothing notable about assigning a value to a
memory location - it happens all over the place in every program,
unless you can figure out what the interesting address ranges are and
then find only the assignments to locations within those ranges, no
debugger or anything will help reverse engineer this kind of design.
back when all communication with devices like was done via inb, outb
instructions and their cousins, it was easier to reverse engineer
things (i did a fair amount of this on the Tropez+ driver, for
example, by running it inside dosemu and tracing all the port io).
--p
This archive was generated by hypermail 2b28 : Thu Nov 08 2001 - 19:36:52 EET