QCA6174 showing terrible performance when connecting via WPA3-SAE

[Kalle Valo]

Eric Park <me at ericswpark.com> writes:

> Hello! I have a Samsung NT500R5H-Y53L with the QCA6174 card, and I
> noticed I was getting terrible performance (around 20-30 Mbps)
> compared to other devices on the network (600-700 Mbps), when running
> a speedtest.
>
> I tried modifying some settings and discovered that I can get around
> 500-600 Mbps on the speedtest if I limited the router settings to
> WPA2-PSK, but once I set the setting to allow for both WPA2 and WPA3,
> the card connects using WPA3-SAE but then has terrible performance as
> a result.
>
> Is this a driver bug, or a limitation of the hardware?

My first guess it's because of software encryption with these cipher
suites (from ath10k_set_key()):

	/* this one needs to be done in software */
	if (key->cipher == WLAN_CIPHER_SUITE_AES_CMAC ||
	    key->cipher == WLAN_CIPHER_SUITE_BIP_GMAC_128 ||
	    key->cipher == WLAN_CIPHER_SUITE_BIP_GMAC_256 ||
	    key->cipher == WLAN_CIPHER_SUITE_BIP_CMAC_256)
		return 1;

But with modern CPUs I would have still expected software encryption to
be faster than 20 Mbps so the chances are it can be something else as
well.

> Is there a way to force the card to connect over WPA2-PSK?

That's a user space decision and depends on what connection manager you
use. For example, here's some info how to setup key management with
Network Manager:

https://askubuntu.com/questions/1290589/how-to-use-wpa3-with-ubuntu-20-04

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