linux-kernel - Re: [PATCH] wireless-2.6 zd1211rw check against regulatory domain rather than hardcoded value of 11

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Message-ID: <454683D1.4030200@deine-taler.de>
Date:	Mon, 30 Oct 2006 23:59:29 +0100
From:	Uli Kunitz <kune@...ne-taler.de>
To:	Johannes Berg <johannes@...solutions.net>
Cc:	Daniel Drake <dsd@...too.org>, Holden Karau <holden@...scanfly.ca>,
	zd1211-devs@...ts.sourceforge.net, linville@...driver.com,
	netdev <netdev@...r.kernel.org>, linux-kernel@...r.kernel.org,
	holdenk@...dros.com
Subject: Re: [PATCH] wireless-2.6 zd1211rw check against regulatory domain
 rather than hardcoded value of 11

Johannes Berg wrote:
>> I'm not so sure about this. This patching might be US-specific and we 
>> cannot simply apply the setting for top channel of another domain 
>> instead of channel 11. One option would be to set the value only under 
>> the US regulatory domain.
> 
> ??
> What the patch does is replace the top channel which is hardcoded to 11
> by the top channel given by the current regulatory domain. How can that
> be wrong? Except that you may want to init the regulatory domain from
> the EEPROM but I'm not sure how the ieee80211 code works wrt. that.
> 
> johannes

The problem is not so much that I don't trust the geo code, but whether
setting the register to that band-edge value for a higher channel is
the right thing to do. It looks like that this is a hack for FFC
compliance. Therefore I suggest to patch CR128 only
for the US regulatory domain.

Here is the code from the GPL vendor driver (zdhw.c):

    if (pObj->HWFeature & BIT_21)  //6321 for FCC regulation, enabled HWFeature 6M band edge bit (for AL2230, AL2230S)
     {
         if (ChannelNo == 1 || ChannelNo == 11)  //MARK_003, band edge, these may depend on PCB layout
         {
             pObj->SetReg(reg, ZD_CR128, 0x12);
             pObj->SetReg(reg, ZD_CR129, 0x12);
             pObj->SetReg(reg, ZD_CR130, 0x10);
             pObj->SetReg(reg, ZD_CR47, 0x1E);
         }
         else //(ChannelNo 2 ~ 10, 12 ~ 14)
         {
             pObj->SetReg(reg, ZD_CR128, 0x14);
             pObj->SetReg(reg, ZD_CR129, 0x12);
             pObj->SetReg(reg, ZD_CR130, 0x10);
             pObj->SetReg(reg, ZD_CR47, 0x1E);
         }
     }

The patch from Holden would set ZD_CR128 to 0x12 for the highest channel,
which would not reflect the logic of the vendor driver.

Kind regards,

Uli

-- 
Uli Kunitz (kune@...ne-taler.de)
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