[OpenWrt-Devel] ath9k-htc init

Alexey Brodkin Alexey.Brodkin at synopsys.com
Thu Nov 26 08:07:24 EST 2015


Hi Jonas,

On Mon, 2015-11-23 at 16:48 +0100, Jonas Gorski wrote:
> On Mon, Nov 23, 2015 at 9:21 AM, Alexey Brodkin
> <Alexey.Brodkin at synopsys.com> wrote:
> > Hi Felix, Jonas,
> > 
> > While playing with my AXS101 board and USB WI-Fi dongles I bumped in
> > a couple of issues. Fortunately I found at least one dongle that
> > works quite nice. That's TP-Link TL-WN721N (or its WN722N sibling)
> > which is based on Atheros AR9271 chip even though it did require
> > one unexpected tweak.
> > 
> > For starters I just selected "kmod-ath9k-htc" in menuconfig and
> > on boot saw USB device recognized, its firmware was loaded,
> > "wifi detect" recognized it as well, see log below.
> > 
> > But then "wlan0" interface was not created on "wifi" command.
> > 
> > After some googling I somehow came to resolution that "hostapd"
> > package installation fixes this problem. And indeed once I got
> > image rebuilt with "CONFIG_PACKAGE_hostapd=y" all worked as expected
> > and I was able to use my board as a Wi-Fi access point.
> > 
> > So the question is if this is expected (requirement for "hostapd")
> > [for "ath9k_htc"]?
> 
> Yes, hostapd[-mini] (or wpad[-mini]) is required for AP mode, and
> wpasupplicant or wpad for encrypted STA mode.

Ooops I didn't realize that right away, indeed I'm trying to setup WiFi
AP and hostAPD (which is really just "host AP Daemon") or alike is a must.

The next question would be which option should I use then?
 1) good olde HostAPD
 2) its -mini sibling
 3) wpad
 4) its -mini sibling

> > Another minor issue is that USB dongle gets recognized a bit late
> > so that automatic "wifi detect" gets already executed and
> > "/etc/config/wireless" isn't created. That requires manual execution of
> > "wifi detect > /etc/config/wireless". Essentially extending delay in
> > "package/base-files/files/etc/init.d/boot" makes a difference:
> > ---------------------->8-------------------
> >         # allow wifi modules time to settle
> >         sleep 15 # instead of 1
> > ---------------------->8-------------------
> > but I'm not sure if we want to do that change for all devices.
> > Then if there's a better way to make auto population of
> > "/etc/config/wireless"?
> 
> Likely the firmware is loaded asynchronously, so the _probe function
> returns quickly. Our workaround in OpenWrt  for other drivers is to
> make the _probe function wait for the firmware to have loaded. and
> thus the wifi device registered in the linux kernel. This will ensure
> the wifi subsystem knows about it when wifi detect is called. This
> seems to be missing for ath9k-htc.

May I get a reference to an example of that workaround?

-Alexey
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