On 12/29/2022 2:52 AM, James Prestwood wrote:
Hi Manikanta,
By the way, userspace itself selects the frequencies to scan, not the
driver.
If we see the split scan implementation in cfg80211, this is the how
it
is implemented. If NL80211_SCAN_FLAG_COLOCATED_6GHZ is set, it
selects
all PSC channels and those non-PSC channels where RNR IE information
is
found in the legacy scan results. If this flag is not set, all
channels
in 6 GHz are included in the scan freq list. It is upto userspace to
decide what it wants.
This isn't your problem, but it needs to be said:
The nl80211 docs need and update to reflect this behavior (or remove
the PSC logic). IMO this is really weird that the kernel selects PSC's
based on the co-located flag. The docs don't describe this behavior and
the flag's name is misleading (its not
SCAN_FLAG_COLOCATED_AND_PSC_6GHZ) :)
Sorry for the late reply, I was on vacation.
What you said make sense. The existing flag should not add PSC channels
according to the flag description.
We can add another flag something like you pointed out
SCAN_FLAG_COLOCATED_AND_PSC_6GHZ and include PSC channels if this flag
is set. What do you say?
If userspace doesn't specify a channel list then the kernel can do
whatever it wants, but otherwise it should stick to the requested
channels and scan only for co-located APs if the flag was set, not
PSC's too.
This basically adds ~3x the time to IWD's quick scan's for 6GHz capable
cards regardless if there are any co-located AP's. ugh.
True.
Thanks,
Manikanta
