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Date: Sat, 4 May 2013 07:49:24 -0700
Message-ID: <CAJ-Vmok2SO3RKuqwvor=jz-pza_NzZugP6-4dfFo3w5NWcQqNw@mail.gmail.com> (sfid-20130504_164929_948392_3AAFB044)
Subject: Re: [ath9k-devel] [PATCH 1/2] ath9k_htc: add STBC TX support
From: Adrian Chadd <adrian@freebsd.org>
To: Felix Fietkau <nbd@openwrt.org>
Cc: Oleksij Rempel <linux@rempel-privat.de>,
	ath9k-devel@lists.ath9k.org, linux-wireless@vger.kernel.org
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On 4 May 2013 04:16, Felix Fietkau <nbd@openwrt.org> wrote:

>> So, should i remove ATH_RC_TX_STBC_FLAG from my patch?
> I extensively reviewed this part, and it's really crazy. Here's what
> happens:
>
> ath_rate_newassoc_11n takes ATH_RC_* flags, converts them to WLAN_RC_*.
> rcSibUpdate_11n interprets the WLAN_RC_* flags as ATH_RC_* and converts
> them to WLAN_RC_* again. For most flags this is pretty much a no-op
> because the definitions are identical.
> For STBC the result 'accidentally' still contains WLAN_RC_STBC_FLAG, but
> only because ath_rate_newassoc_11n converts ATH_RC_RX_STBC_FLAG to
> WLAN_RC_STBC_FLAG and WLAN_RC_STBC_FLAG overlaps with ATH_RC_TX_STBC_FLAG.
> In the end it doesn't matter anymore, because nothing in the code takes
> the STBC info from the capflags.
>
> STBC is used if ATH_NODE_ATHEROS(an)->stbc is non-zero, and this gets
> set by ath_rate_newassoc_11n before all of those incredibly moronic
> conversions happen.

It smells like left-over from the 7.x driver code this is based off of.



Adrian