Message-ID: <4F8B1312.2010108@openwrt.org> (sfid-20120415_202747_155660_0A1A365F)
Date: Sun, 15 Apr 2012 20:27:30 +0200
From: Felix Fietkau <nbd@openwrt.org>
MIME-Version: 1.0
To: Daniel Halperin <dhalperi@cs.washington.edu>
CC: linux-wireless@vger.kernel.org, linville@tuxdriver.com,
	mcgrof@qca.qualcomm.com
Subject: Re: [PATCH 2/9] ath9k_hw: do not override SIFS time for half/quarter
 channels
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On 2012-04-15 8:22 PM, Daniel Halperin wrote:
> Felix,
> 
> This whole patch series throws the NICs out of spec compliance. For
> instance, page 626 of the 802.11-2007 standard (Table 17-15) says that
> aSIFStime is 32 us in 10 MHz mode and 64 us in 5 MHz mode.
> 
> This might be okay to do for certain implementations (as, apparently,
> AR9280/AR9380), but will break compatibility with any device obeying
> the standard instead.
> 
> (I wonder that, if this code below still works, then it seems that you
> might not be properly downclocking the chips' reference clock...)
> 
> Are you aware there's a standard for this? Why violate it?
I'm aware that there's a standard for it, but if I put in the standard
values, the connection gets unreliable to the point where it's almost
unusable. That's why I chose to use existing products with 5/10 MHz
support as reference instead.

- Felix