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Re: [gNewSense-users] ubuntu/media/gspcav1 full of hex tables

From: Peter and Jesse
Subject: Re: [gNewSense-users] ubuntu/media/gspcav1 full of hex tables
Date: Mon, 23 Jun 2008 12:37:17 -0700

On Sat, 2008-06-21 at 22:20 +0200, Carsten Agger wrote:
> On Sat, 2008-06-21 at 15:12 +0200, Sam Geeraerts wrote:
> > Peter and Jesse wrote:
> > > Almost every file in the directory ubuntu/media/gspcav1/ is full of hex
> > > tables. Many of them have names like static __u16
> > > [driver_name]_start_data[][3].
> > > 
> > > Also, several of these files (in different directories) are identified
> > > as needing binary firmware on
> > >  Peter
> > > 
> > 
> > I've looked at a few of those files and it looks like most (all?) of 
> > them are copyrighted by private individuals rather than companies. Some 
> > of the comments say that the data has been reverse engineered by way of 
> > USB snooping. I believe most webcams are similar to Winmodems: almost 
> > all of the action happens in software. I can imagine that such software 
> > would include some magic initialization data.
> > 
> > I think the authors did enough snooping to get the devices to work, but 
> > didn't bother to dig into it deeper to find out what all command codes 
> > and data actually meant. Comments on some lines indicate that they did 
> > find out for some parts of it.
> > 
> > Despite the large amount of hex values and the code being rather terse 
> > and vague, I don't think the code has been deliberately obfuscated. So I 
> > think these files can be marked as free. I also don't immediately see 
> > any evidence of a requirement for proprietary firmware apart from the 
> > files that are included.
> > 
> > This is just my subjective opinion. I don't know how these drivers are 
> > usually developed. As long as someone more knowledgeable in this field 
> > or one or more of the authors haven't confirmed this, it's probably 
> > safer to mark them as non-free.
> Maybe it would be a good idea to contact some of the individuals
> credited with the code or perhaps somebody knowledgeable in this kind of
> development to clear this up - possibly somebody in kernel development
> or similarly? Who would that be?

I have contacted the copyright holders for
ubuntu/media/gspcav1/Vimicro/cs2102.h. I have received the following:
"These values are reverse engineered the usb protocole between the
webcam and a windoze box."

I don't think it make sense to try to contact the authors of every file.
cs2102.h seems to be one of the most hex-intensive files, so if it is
reverse-engineered, I think that similar files probably are as well. I
am inclined to mark these as free.

 Peter Stevenson

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