Re: A good way to get CSI info to user-space?

[Johannes Berg <johannes@sipsolutions.net>]

Hi,

> I have been poking at ath10k to get some CSI reporting working.
> The CSI reports are a bit over 2k bytes in length, and they could
> happen quite often.  As far as I can tell, there is no good way in
> the kernel to make this available.
> 
> I was thinking maybe a callback into the mac80211 stack, which would
> then send a netlink event might be a useful way to implement this?

The CSI data has variable length [1] but it's fundamentally always tied
to a specific frame and as such we've always attached it to that frame
using a radiotap vendor namespace.

You can easily implement that in a mac80211 driver since it has support
for that via RX_FLAG_RADIOTAP_VENDOR_DATA and the associated struct
ieee80211_vendor_radiotap that you put into the skb's head.

Why should anything else be needed?

johannes

[1] mostly depending on the bandwidth