On Tue, Sep 27, 2016 at 05:36:26PM +0200, Stefan Sperling wrote:
> It looks like iwm firmware does not like a MAC context which does not
> specify the AP's BSSID.
> 
> The driver currently adds such a context when initializing the hardware
> for the first time after boot (with the BSSID set to all zeros, I also tried
> a broadcast address and that doesn't work either).
> This then triggers the well-known performance bug for some reason which
> only Intel engineers with magic spell books can figure out.
> 
> I noticed performance is fixed after running 'ifconfig iwm0 scan' once.
> This brings the interface down and runs the same hardware init sequence,
> but this time it copies the now cached BSSID from ic->ic_bss into the mac
> context command and things start working.
> 
> This diff makes sure we don't add a MAC context before we know the BSSID.
> Now things start working correctly right after boot.
> 
> I've tested this on 8260 hardware only so far, AFAIK all HW is affected
> by this problem. Additional testing appreciated.

Just as the earlier version of this patch that you sent in private, this
fixes the issues I saw on my

iwm0 at pci2 dev 0 function 0 "Intel Dual Band Wireless AC 7265" rev 0x59, msi
iwm0: hw rev 0x210, fw ver 16.242414.0, address 11:22:33:44:55:66

It's a massive improvement, thanks!

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