rtl8187b: puzzled at reg_table

Alexandre Oliva lxoliva at fsfla.org
Fri Jan 2 05:34:43 UTC 2009

Hi, Larry, Johnny, Andrea,

Happy GNU Year to you all!

On Jul  9, 2008, Larry Finger <Larry.Finger at lwfinger.net> wrote:

> Alexandre Oliva wrote:
>> I'm trying to make sense of this:

>> static const u8 rtl8187b_reg_table[][3] = {
>> {0xF0, 0x32, 0}, {0xF1, 0x32, 0}, {0xF2, 0x00, 0}, {0xF3, 0x00, 0},

> It is black magic!!

> The vendor's driver has the same table named MAC_REG_TABLE

> This driver is essentially reverse-engineered, even though there is a
> vendor-supplied driver.

Back then, I mistook what you wrote as implying the vendor's driver was
non-Free, and didn't look into it any further.  I hope you don't mind
that I'm now copying the linux-libre list with snippets from your

Now, prompted by a Linux-libre user request, I got myself looking into
it again, and I found out the driver you alluded to was released under
the GPL.

I see that Andrea thanks Realtek Corp for the support, in
8180_rtl8225z2.c, and at
Johnny claims to have obtained that driver from realtek.

This is good, if confirmed, because then Realtek will have distributed
the table above under the GPL, so in theory it wouldn't be able to use
its copyright power to stop people from redistributing, which was one my
of concerns.

Johnny, can you please confirm that you got the code from realtek, and
how that happened?  I couldn't find alternate sources for this driver
straight from Realtek, but I can't say I looked for it real hard :-)

Andrea, I realize you wrote the code some 3+ years ago, but I wonder...
Do you happen to remember where the numbers came from for this
MAC_REG_TABLE, related with WPA configuration in rtl8187b?  It would be
nice to have a few comments explaining the meaning of those bits, so
that one could change them to suit one's own needs, or even improve it.
Is there, by any chance, any documentation you could point us to, where
you got instructions to come up with those numbers?

> We are now in contact with Realtek and there is hope of getting their
> input on this device.

Any news on this front?

Thanks in advance.  Looking forward to a positive response from you all.

Best regards,

Alexandre Oliva           http://www.lsd.ic.unicamp.br/~oliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/   FSF Latin America board member
Free Software Evangelist      Red Hat Brazil Compiler Engineer

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