RE: [EXT] Re: [PATCH v9 0/2] wifi: mwifiex: add code to support host mlme

David Lin
2024-04-10T10:33:23Z

> From: Johannes Berg <johannes@sipsolutions.net>
> Sent: Wednesday, April 10, 2024 3:55 PM
> To: David Lin <yu-hao.lin@nxp.com>; Brian Norris
> <briannorris@chromium.org>
> Cc: Francesco Dolcini <francesco@dolcini.it>; kvalo@kernel.org;
> linux-wireless@vger.kernel.org; linux-kernel@vger.kernel.org; Pete Hsieh
> <tsung-hsien.hsieh@nxp.com>; rafael.beims <rafael.beims@toradex.com>;
> Francesco Dolcini <francesco.dolcini@toradex.com>
> Subject: Re: [EXT] Re: [PATCH v9 0/2] wifi: mwifiex: add code to support host
> mlme
>
> On Wed, 2024-04-10 at 07:30 +0000, David Lin wrote:
> > Hi Johannes and Brian,
> >
> > I think this patch is used to leverage MLME of wpa_supplicant and
> hostapd. It won't affect the usage of cfg80211 for mwifiex. I wonder if I can
> prepare patch v10.
>
> No. That sentence tells me you've _still_ not understood any of the technical
> arguments in the thread, you're _still_ arguing with completely uninteresting
> arguments. Where before you had "it's well tested" and "it uses 'standard'
> APIs" now you're saying "it doesn't affect anyone else". All of that is obvious,
> and also completely besides the point.
>
> Please go back and actually _understand_ the discussion. Also actually
> _participate_ in the discussion too, so far you've pretty much only made empty
> arguments. Once you've understood the concerns and can explain why they
> don't apply, _then_ you can resend the patch.
>
> johannes

Take Rx data path as an example,
In current FW, BA stream setup and de-ampdu are handled in FW. Packet is converted to 802.3 before passing to host. Ampdu reordering is handled in host driver (Mwifiex) due to memory consideration. We used to work on a driver that uses RX_FLAG_8023. It was on an older Wi-Fi part which has more memory and powerful processor. But with this chip buffer required for reordering doesn’t fit FW memory.

Ampdu reordering needs MAC 802.11 header, FW keeps the MAC header in packet descriptor since packet already 802.3 when arrive at driver. As packet descriptor only accessible in the driver, Mwifiex handles the reordering instead of using mac80211 reordering.

With current FW design, to apply mac802.11 we either change FW to pass packet in 802.11 format or driver needs to do the conversion back to 802.11 (which I think doesn’t make sense)

Given existing FW design, we think it’s difficult to apply mac80211. Hope this make valid arguments.

David