Re: [PATCH] rtl8187b: do not do per packet TX AGC

[Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>]

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On Sat, Aug 28, 2010 at 04:32:48PM -0500, Larry Finger wrote:
> On 08/28/2010 12:54 AM, Thadeu Lima de Souza Cascardo wrote:
> > The code for rtl8187 does not do per packet TX AGC. Resetting the per
> > packet TX AGC for rtl8187b appears to increase its overall TX power.
> > This allows the device to associate and a connection be established
> > using APs a little further away.
> > 
> > Tested-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
> > Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
> > Cc: linux-wireless@vger.kernel.org
> > Cc: Larry Finger <Larry.Finger@lwfinger.net>
> > Cc: Rogerio Luz Coelho <rogluz.news@gmail.com>
> > Cc: Herton Ronaldo Krzesinski <herton@mandriva.com.br>
> > Cc: Hin-Tak Leung <hintak.leung@gmail.com>
> > ---
> 
> I'm a little confused here. The subject says not to set the per packet TX AGC,
> while the submission text says that setting it helps. I don't have access to any
> documents that describe this register, but I expect that clearing
> RTL818X_TX_AGC_CTL_PERPACKET_GAIN_SHIFT would disable that feature. As a result
> the code change seems to match the subject.

Hello, Larry.

I meant rtl8187 versus rtl8187b, since the driver does that distinction.
You may note that in function rtl8187_start, if priv->is_rtl8187b fails,
it will reset RTL818X_TX_AGC_CTL_PERPACKET_GAIN_SHIFT, just before
writing to TX_CONF. That's why I've decided to do it too before writing
in TX_CONF in the priv->is_rtl8187b true case.

And I meant resetting and "setting to zero". Perhaps, I may clarify that
too.

> 
> I have not yet tested this code, but I do note that all the Realtek drivers for
> the RTL8187B set this bit.
> 

Well, rtl8187B_linux_26.1056.1112.2009.release does reset it to zero
too. And that's what has hit me into trying it.

> Until testing, I withhold judgment on the actual code change, but NACK for the
> inconsistency.
> 

I will send another version, clarifying the commit message. Thanks for
the comments.

Regards,
Cascardo.

> Larry
> 

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