[linux-dvb] Re: Difference btw Binary Only Kernel Modules and Firmware

[Michael Hunold <hunold@convergence.de>]

Hello Egon,

> Now I ask myself what is difference between binary only kernel modules
> and the binary only firmware in the DVB driver?
You have to distinguish *where* your binary only code is running.

The code from a binary only kernel module is running on your host cpu 
and threatens the stability of your kernel, ie. the whole system is 
affected.

A binary only firmware for your DVB card (or your sound card, ...) only 
affects the stability of the card, because the code runs on a separate 
processor on your card. If the kernel driver is open source and handles 
all error conditions correctly, you system stability should not be affected.

Basically there is no difference between a function that is implemented 
by a general-purpose processor using a firmware or by a dedicated 
chipset where the same functionality is present in silicon. If you the 
necessary specifications (ie. register and address descriptions), 
writing a driver is the same.

Giving out the source code for the firmware that runs on the processor 
won't help the average developer, because a special toolchain (compiler, 
assembler, linker) might be needed to compile the code into a new 
firmware. And on the other hand, you won't ask a vendor to hand out 
their design sheets for their dedicated chipsets which do the same as 
the av7110 with a firmware, won't you?

IMHO it's ok to have firmware in dedicated processors on extension 
hardware, as long as you have access to the necessary specifications for 
the communication protocol with other parts of the system (which is 
lacking for the av7110 firmware I admit)

> The following appear to be contradictions in terms:
> Linux developers want to be able to examine every piece of critical code.
> Software producers are looking for a way to protect their IP.
But you are not referring to software developers when asking about the 
DVB firmware, aren't you?

None of the companies that are usually being criticised (Nvidia, VIA, 
Sigma Designs) actually sells software, they only sell hardware.

IMHO there is *no* point that they don't open up their drivers, there is 
nothing really interesting in them. (Ok, perhaps they do 
software-workarounds for hardware-bugs they have, or you'll see that 
they emulate things in software that the hardware should do, ...)

For software companies that rely on software patents and IP this is a 
whole different story.

> Can the firmware approach help to resolve this conflict? Or is it just
> another name for the same old game? I am grateful for your comments.
As I have explained above, firmware is IMHO ok, because it only affects 
one component and provides the functionality a dedicated chipset usually 
has. This only applies if you have access to the necessary 
specifiactions of course.

It does not matter if you don't have the chipset specifactions for a 
dedicated chipset or a chipset with a processor using a firmware.

Don't buy the hardware then. ;-)

> Best regards
> Egon
CU
Michael.


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