Re: [PATCH 2/3] ath9k_hw: clean up per-channel calibration data

["Luis R. Rodriguez" <lrodriguez@atheros.com>]

On Wed, Jul 28, 2010 at 10:45 AM, Felix Fietkau <nbd@openwrt.org> wrote:
> The noise floor history buffer is currently not kept per channel, which
> can lead to problems when changing channels from a clean channel to a
> noisy one. Also when switching from HT20 to HT40, the noise floor
> history buffer is full of measurements, but none of them contain data
> for the extension channel, which it needs quite a bit of time to recover
> from.
>
> This patch puts all the per-channel calibration data into a single data
> structure, and gives the the driver control over whether that is used
> per-channel or even not used for some channels.
>
> For ath9k_htc, I decided to keep this per-channel in order to avoid
> creating regressions.
>
> For ath9k, the data is kept only for the operating channel, which saves
> some space. ath9k_hw takes care of wiping old data when the operating
> channel or its channel flags change.
>
> Signed-off-by: Felix Fietkau <nbd@openwrt.org>

But this also means every time we want to get operational on a channel
we have to learn the current noise all over again. This means for WiFi
Direct every channel swap we'd have to learn to walk, which happens
quite often. What do you think? Sorry, I know we discussed this
approach and I seemed fine but this just occurred to me now, and will
become really important later when we support WiFi Direct.

  Luis