When wifi radio is reset, some bits in (undocumented) USB registers may
flip. Patch adds setting them after radio reset (channel change, up/down).
With this patch stability of USB1.1 full-speed devices, connected directly
to AR9331 host port (no USB2.0 hub) is improved.
See "ar9331's usb stability issue" OpenWrt forum thread for details:
<https://forum.openwrt.org/viewtopic.php?id=39956>
Based on QCA's Open HAL WAR_USB_DISABLE_PLL_LOCK_DETECT() macro:
<https://github.com/qca/qcamain_open_hal_public/blob/master/hal/ar9300/ar9300_reset.c#L74>
Adapted to Linux mac80211 driver for 8Devices Carambola2 board by Mantas Pucka:
<b08b59ceb4>
Ported to latest OpenWrt BB branch and tested on TP-Link TL-WR703N by
Michel Stempin <michel.stempin@wanadoo.fr>.
Signed-off-by: Michel Stempin <michel.stempin@wanadoo.fr>
[juhosg: refresh and clean up the ath9k patch]
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
SVN-Revision: 39212
