linux-wireless.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Felix Fietkau <nbd@openwrt.org>
To: "Luis R. Rodriguez" <lrodriguez@atheros.com>
Cc: Bruno Randolf <br1@einfach.org>,
	johannes@sipsolutions.net, linville@tuxdriver.com,
	linux-wireless@vger.kernel.org
Subject: Re: [PATCH v4 1/3] cfg80211: Add nl80211 antenna configuration
Date: Tue, 27 Jul 2010 18:39:13 +0200	[thread overview]
Message-ID: <4C4F0BB1.6030002@openwrt.org> (raw)
In-Reply-To: <AANLkTi=4BtktKxPmFnYwAHaf9Wg-VdLmupcOfXEr1Bpg@mail.gmail.com>

On 2010-07-27 6:19 PM, Luis R. Rodriguez wrote:
>> + * @NL80211_ATTR_WIPHY_ANTENNA_TX: Bitmap of allowed antennas for transmitting.
>> + *     Each bit represents one antenna, starting with antenna 1 at the first
>> + *     bit. If the bitmap is zero (0), the TX antenna follows RX diversity.
> 
> What about for 802.11n? What if you want to disable TX?
Disabling tx shouldn't be handled by the antenna setting, IMHO.

>> + *     If multiple antennas are selected all selected antennas have to be used
>> + *     for transmitting (801.11n multiple TX chains).
> 
> I rather call this TX / RX chainmask then.
Well, for legacy hardware, these aren't really chains, as there is only
one rx and one tx path, just with switching onto multiple antennas.

>> + *     Drivers may reject configurations they cannot support.
>> + *
>> + * @NL80211_ATTR_WIPHY_ANTENNA_RX: Bitmap of allowed antennas for receiving.
>> + *     Each bit represents one antenna, starting with antenna 1 at the first
>> + *     bit. If multiple antennas are selected in the bitmap, 802.11n devices
>> + *     should use multiple RX chains on these antennas, while non-802.11n
>> + *     drivers should use antenna diversity between these antennas.
> 
> What about TX beamforming, and STBC?
Disabling one antenna/chain on a two-chain device would naturally
disable TxBF and STBC as well, since it limits the number of available
chains. The driver should simply act as if the disabled chains didn't exist.

> Unless 802.11n is completely dealt with I really prefer this patch to
> only address legacy. Otherwise I see sloppyness and inconsistencies on
> supporting this feature throughout different drivers. I'd like to
> avoid that at all costs on nl80211. What you are trying to address is
> legacy antenna setup, not 802.11n RX/TX chainmask dynamic settings so
> I'd really try to avoid it unless you really want to address all
> aspects of chain configuration for 802.11n and even then what I'm
> leading on to say is I think you'll see if you try to address both it
> just gets messy.
I think 802.11n is already completely dealt with if you treat this as
the chainmask on 11n devices.

- Felix

  reply	other threads:[~2010-07-27 16:39 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-07-27  9:47 [PATCH v4 0/3] Antenna configuration Bruno Randolf
2010-07-27  9:48 ` [PATCH v4 1/3] cfg80211: Add nl80211 antenna configuration Bruno Randolf
2010-07-27 10:05   ` Johannes Berg
2010-07-28  2:03     ` Bruno Randolf
2010-07-27 16:19   ` Luis R. Rodriguez
2010-07-27 16:39     ` Felix Fietkau [this message]
2010-07-27 16:47       ` Luis R. Rodriguez
2010-07-28  2:06         ` Bruno Randolf
2010-07-28 17:24           ` Luis R. Rodriguez
2010-07-28 17:50             ` Felix Fietkau
2010-07-28 21:15               ` Luis R. Rodriguez
2010-07-28 21:26                 ` Felix Fietkau
2010-07-28 21:39                   ` Luis R. Rodriguez
2010-07-28 22:05                     ` Felix Fietkau
2010-07-28 22:14                       ` Luis R. Rodriguez
2010-07-29  0:10                       ` Luis R. Rodriguez
2010-07-29  2:11             ` Bruno Randolf
2010-07-29 15:09               ` Luis R. Rodriguez
2010-08-02  3:59                 ` Bruno Randolf
2010-08-02  5:31                   ` Luis R. Rodriguez
2010-07-27  9:48 ` [PATCH v4 2/3] mac80211: Add " Bruno Randolf
2010-07-27  9:48 ` [PATCH v4 3/3] ath5k: Add support for " Bruno Randolf

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=4C4F0BB1.6030002@openwrt.org \
    --to=nbd@openwrt.org \
    --cc=br1@einfach.org \
    --cc=johannes@sipsolutions.net \
    --cc=linux-wireless@vger.kernel.org \
    --cc=linville@tuxdriver.com \
    --cc=lrodriguez@atheros.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).