Re: AP mode with Broadcom 4330

[Russell King - ARM Linux <linux@armlinux.org.uk>]

On Tue, Aug 15, 2017 at 10:58:42AM +0100, Russell King - ARM Linux wrote:
> Sorry for the confusion - the problem with iwlwifi turned out to be a
> lack of /dev/random entropy, causing hostapd to forcefully deauth the
> client - that was hidden when running hostapd from systemd and is only
> visible if you run hostapd manually.
> 
> (I have other problems there - manually starting hostapd works every
> time, but when started using systemctl start hostapd, systemctl status
> hostapd always reports that it's started but exited and it definitely
> isn't running... I'm just hitting one problem after another here with
> wireless, I'm quite sure this tech hates me!)
> 
> However, I'm still having problems with the Realtek not getting further
> than _allegedly_ sending the auth frames - I'm not convinced that the
> driver is actually sending anything yet.  I can't see anything suggesting
> it is from iwlwifi in monitor mode, and enabling all the debug for the
> rtl8xxxu driver doesn't give the slightest hint that this driver is
> doing anything remotely useful to transmit these frames.  For instance:
> 
> [41742.979480] usb 1-1: rtl8xxxu_read32(0440)  = 0x0000000f, len 4
> [41742.985826] usb 1-1: rtl8xxxu_write32(0440) = 0x0000000f
> [41742.994470] usb 1-1: rtl8xxxu_write8(0480) = 0x04
> [41742.999430] wlan0: send auth to 6c:ad:f8:1d:4c:d9 (try 1/3)
> [41743.206163] wlan0: send auth to 6c:ad:f8:1d:4c:d9 (try 2/3)
> [41743.414148] wlan0: send auth to 6c:ad:f8:1d:4c:d9 (try 3/3)
> [41743.622138] wlan0: authentication with 6c:ad:f8:1d:4c:d9 timed out
> [41743.629100] usb 1-1: rtl8xxxu_write8(0618) = 0x00
> [41743.636490] usb 1-1: rtl8xxxu_write8(0619) = 0x00
> [41743.641573] usb 1-1: rtl8xxxu_write8(061a) = 0x00
> 
> How can it send auth packets without writing to any registers (this is
> with all debug options set in /sys/module/rtl8xxxu/parameters/debug !)
> 
> So, I don't think the 4330 has a problem, I think it's all down to
> the Realtek driver being buggy.

And things get even weirder - if I reboot, rtl8xxxu fails to associate:

[   38.377649] wlan0: authenticate with 6c:ad:f8:1d:4c:d9
[   38.410252] wlan0: send auth to 6c:ad:f8:1d:4c:d9 (try 1/3)
[   38.616678] wlan0: send auth to 6c:ad:f8:1d:4c:d9 (try 2/3)
[   38.824660] wlan0: send auth to 6c:ad:f8:1d:4c:d9 (try 3/3)
[   39.032645] wlan0: authentication with 6c:ad:f8:1d:4c:d9 timed out

if I then rmmod the rtl8xxxu module and reinsert the exact same module:

[   49.914724] wlan0: authenticate with 6c:ad:f8:1d:4c:d9
[   49.935765] wlan0: send auth to 6c:ad:f8:1d:4c:d9 (try 1/3)
[   49.943182] wlan0: authenticated
[   49.956116] wlan0: associate with 6c:ad:f8:1d:4c:d9 (try 1/3)
[   49.971504] wlan0: RX AssocResp from 6c:ad:f8:1d:4c:d9 (capab=0x411 status=0 aid=2)
[   49.985466] usb 1-1: rtl8xxxu_bss_info_changed: HT supported
[   49.997918] wlan0: associated

This looks like a rtl8xxxu driver / core mac80211 bug, so I'll take it
to the rtl8xxx folk now.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
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