Hi Manikanta, > Currently, time taken to scan all supported channels on WCN6750 > is ~8 seconds and connection time is almost 10 seconds. WCN6750 > supports three Wi-Fi bands (i.e., 2.4/5/6 GHz) and the numbers of > channels for scan come around ~100 channels (default case). > Since the chip doesn't have support for DBS (Dual Band Simultaneous), > scans cannot be parallelized resulting in longer scan times. > > Among the 100 odd channels, ~60 channels are in 6 GHz band. Therefore, > optimizing the scan for 6 GHz channels will bring down the overall > scan time. > > WCN6750 firmware has support to scan a 6 GHz channel based on co-located > AP information i.e., RNR IE which is found in the legacy 2.4/5 GHz scan > results. When a scan request with all supported channel list is enqueued > to the firmware, then based on WMI_SCAN_CHAN_FLAG_SCAN_ONLY_IF_RNR_FOUND > scan channel flag, firmware will scan only those 6 GHz channels for which > RNR IEs are found in the legacy scan results. > > In the proposed design, based on NL80211_SCAN_FLAG_COLOCATED_6GHZ scan > flag, driver will set the WMI_SCAN_CHAN_FLAG_SCAN_ONLY_IF_RNR_FOUND flag > for non-PSC channels. Since there is high probability to find 6 GHz APs > on PSC channels, these channels are always scanned. Only non-PSC channels > are selectively scanned based on cached RNR information from the legacy > scan results. > > If NL80211_SCAN_FLAG_COLOCATED_6GHZ is not set in the scan flags, > then scan will happen on all supported channels (default behavior). is this really a good idea? The interpretation on what scan results will be reported would be preferable the same no matter what hardware is present. Why would ath11k now have a different behavior? And more important, why is this something driver or even Linux kernel specific. Let userspace select the frequencies to scan. Looks like that iwd and wpa_supplicant set this flag regardless which means to me that a driver should respect the requested frequencies to be scanned. Anyhow, if you worry about time-to-connect, then fix userspace to be smart with scanning. I am also confused on how a savings of 1.5 seconds out of 8 seconds is significant. It still means you spent 6+ seconds in the 2.4 GHz and 5 GHz bands. I assume that you spent most time in 5 GHz right now. I highly doubt that a 6+ seconds plus 2 seconds connection time is anywhere acceptable. Have you tried using iwd and see what the connection time actually is after initial connection. Regards Marcel
