[Qemu-devel] Cirrus Logic

[Qemu-devel] Cirrus Logic

[Hetz Ben Hamo]

Hi,

I did some research about Cirrus Logic and it's graphics chipsets.

On October 13, 1998, the company sold it's graphics business to ISDCorp 
see: http://www.cirrus.com/en/press/releases/P136.html

If you go to www.isdcorp.com, you'll be headed to (drum rolls...) - 
http://www.embeddedsoftwaregroup.com/ which is an embedded Linux 
software company. The only part about Cirrus Logic there is their old 
drivers (Windows 3.1 drivers anyone? :)

So there you go. all their chip business is dead some 7 years now, and 
the company doesn't do anything with it (they port Linux to various 
architectures, if anyone really wants to know), I hardly belive that 
someone would care about it. Heck, I'm willing to host the code on my 
server if it's so much problem...

Thanks,
Hetz

Re: [Qemu-devel] Cirrus Logic

[Bartosz Fabianowski]

> On October 13, 1998, the company sold it's graphics business to
> ISDCorp

Not quite. What they transferred was the PC graphics software team.
Nothing is said in that press release about the hardware side of things.

> If you go to www.isdcorp.com, you'll be headed to (drum rolls...) - 
> http://www.embeddedsoftwaregroup.com/

Yes. And if you click on the "Cirrus Logic" logo in the lower left
corner of the website, you will see a disclaimer. Among other things, it
states:

"Embedded Software Group (ESG) is not part of Cirrus Logic Corporation
and does not manufacture the Cirrus Logic Graphics Chips, Graphics Cards
or Motherboards."

So again, the hardware part of Cirrus' graphics business was not
transferred to ISDCorp, while the software side was:

"ESG is an independent software company specializing in the development
of the software device drivers that allow peripheral devices to work
with your operating system."

> [...] I hardly belive that someone would care about it. Heck, I'm
> willing to host the code on my server if it's so much problem...

I agree that it is very unlikely anybody would care. Most developers 
also find it boring and annoying to try and figure out the legalities 
behind every little step they take. I personally just happen to be 
interested in the legal matters behind things. That is why I posed the 
question in the first place and that is why I am still interested in 
seeing whether I can get official permission from Cirrus. Not that 
others care, I just consider this an interesting task for myself.

- Bartosz

Re: [Qemu-devel] Cirrus Logic

[John R. Hogerhuis]

On Wed, 2004-06-02 at 04:35, Bartosz Fabianowski wrote:

> I agree that it is very unlikely anybody would care. Most developers 
> also find it boring and annoying to try and figure out the legalities 
> behind every little step they take. I personally just happen to be 
> interested in the legal matters behind things. That is why I posed the 
> question in the first place and that is why I am still interested in 
> seeing whether I can get official permission from Cirrus. Not that 
> others care, I just consider this an interesting task for myself.
> 

I too take interest in these legal issues that crop up.

However, I'm not sure why use of the manuals is an interesting legal
issue when there's no obvious legal issue...

I've never heard using published documentation to implement a clone or
emulation of something being an issue unless you are under NDA or it
involves a patented algorithm. Am I not understanding the problem? Can
you think of an example of such a case? I wonder if Microsoft has a
similar clause in their Win32 documentation, and whether that would stop
the Wine project. And would Microsoft give their permission? If they
could effectively do this, Microsoft would have done this to head off
Wine.

In any event, if you do find someone to ask the convervative answer from
their lawyers would most likely be "no." That's the knee-jerk reaction
when their shareholder interest is orthogonal to the request or possibly
could negatively impact their shareholders. Then what?

Is there any positive interest for the shareholders? If you were to get
a positive response, you'd have to come up with some reasoning that
shows that it is in their shareholders interest to allow their
documentation and hardware to be used to make an emulation. Otherwise I
can almost promise that you will get a "no."

Better to ask forgiveness than permission in some cases.

You'd be more likely to get the answer you want from an independent
lawyer than the successors-in-interest of Cirrus whoever they may be.

-- John.

Re: [Qemu-devel] Cirrus Logic

[Bartosz Fabianowski]

> I've never heard using published documentation to implement a clone 
> or emulation of something being an issue unless you are under NDA or
> it involves a patented algorithm. Am I not understanding the
> problem?

I don't anticipate the emulation of a graphics card itself to be an
issue. Unless, of course, that emulation infringes on some trademarks,
trade secrets, patents, the DMCA or some other rule that I can't think
of right now. What I think is problematic though is the way in which the
information needed to program the emulation is acquired.

When documentation is published without any disclaimer, there might be
no issue. However, in this case, the documentation we are talking about
specifically states that you are not allowed to create or sell any items
based on it. The very purpose of this disclaimer seems to be to prevent
the competition from reading the documentation and creating clones based
on it.

Of course QEMU can hardly be considered a competitor and since the chip
is several years old, Cirrus Logic probably doesn't care whether QEMU
uses the documentation to implement an emulation or not. However,
legally, that does not mean the disclaimer is any less valid, expired,
or not apply to QEMU. And this is the issue I am interested in. I am
wondering whether it would be possible to obtain from Cirrus Logic the
express permission to use the documentation in order to implement an
emulation of their chip.

> I wonder if Microsoft has a similar clause in their Win32 
> documentation, and whether that would stop the Wine project.

That's a very interesting question along the same lines as the Cirrus
Logic issue. I have read excerpts from the Win32 SDK documentation when
I needed them, but I never looked at any introductory chapters or
disclaimers. If there is a similar clause in there, the Wine people will
have probably given it some thought already and one could ask them to
what conclusion they came.

> In any event, if you do find someone to ask the convervative answer 
> from their lawyers would most likely be "no." That's the knee-jerk 
> reaction when their shareholder interest is orthogonal to the request
> or possibly could negatively impact their shareholders. Then what?

Yes, I anticipate that answer as well. Even if QEMU does not hurt them,
they might just say "no" to be on the safe side, not to permit anybody
to do anything if they don't have to. Now, if the only legal issue is
with using their documentation, that shouldn't be too hard to resolve.
One way would be to simply not use the documentation. Use other -
acceptable - ways of obtaining information about how the chip works. The
other way to solve the problem would be if it turns out that for one
reason or another the disclaimer does not apply. The Wine folks might
come in handy at that point should they have dealt with a similar issue
already.

> If you were to get a positive response, you'd have to come up with 
> some reasoning that shows that it is in their shareholders interest 
> to allow their documentation and hardware to be used to make an 
> emulation. Otherwise I can almost promise that you will get a "no."

Having the legacy of their chip design live on is pretty much all I can
think of and that is hardly going to motivate them.

> Better to ask forgiveness than permission in some cases.

Quite often, that is probably all that's left. Very unfortunate though
because I would like to resolve this nicely.

> You'd be more likely to get the answer you want from an independent 
> lawyer than the successors-in-interest of Cirrus whoever they may be.

I still don't think Cirrus Logic sold their graphics hardware business
to anybody, so it should still be Cirrus you'd need to talk to.

- Bartosz

PS: And here's my own little disclaimer - better be safe than sorry. I
am not a lawyer and all that I wrote in this mail is my personal opinion.

Re: [Qemu-devel] Cirrus Logic

[Hetz Ben Hamo]

> I don't anticipate the emulation of a graphics card itself to be an
> issue. Unless, of course, that emulation infringes on some trademarks,
> trade secrets, patents, the DMCA or some other rule that I can't think
> of right now. What I think is problematic though is the way in which the
> information needed to program the emulation is acquired.

After doing some thinking, I think I found some sort of solution:

A configure switch - just like ffmpeg has these days...

If a company or a person wants not to take a risk - then just leave the 
current VGA implementation there and let the developer use a switch to 
use it. Else - use the newer implementations...

And in case no one has looked - QEMU is all about plugins - whether it's 
processor, IDE, floppy, VGA, etc - you can just write another plugin 
just like we have ARM, PPC, SPARC ...

Thanks,
Hetz