On Wed, Jul 28, 2010 at 02:30:24PM -0700, Felix Fietkau wrote: > On 2010-07-28 11:21 PM, Luis R. Rodriguez wrote: > > On Wed, Jul 28, 2010 at 2:10 PM, Felix Fietkau <nbd@xxxxxxxxxxx> wrote: > >> On 2010-07-28 10:52 PM, Luis R. Rodriguez wrote: > >>> On Wed, Jul 28, 2010 at 10:45 AM, Felix Fietkau <nbd@xxxxxxxxxxx> 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@xxxxxxxxxxx> > >>> > >>> 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. > >> When we get to implementing per-vif channel settings with switching > >> being done in mac80211, we can just move the calibration data to ath9k's > >> virtual interface data and thus keep the calibration for multiple > >> operating channels. > > > > Sounds good. This would currently break the ath9k virtual wiphy's > > calibration stuff :P (not like I care), Jouni? > > My current patch should work just fine with virtual wiphy's, since I > store the calibration data in the ath_wiphy struct. Ah neat, this approach seems fine in the long run then. My only remaining questions is how effective our scans are in a noisy environemnt with what I suppose are some default settings? Luis -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
