Sven Eckelmann <sven@xxxxxxxxxxxxx> wrote:
> Some ETSI countries have a small overlap in the wireless-regdb with an ETSI
> channel (5590-5650). A good example is Australia:
>
> country AU: DFS-ETSI
> (2400 - 2483.5 @ 40), (36)
> (5150 - 5250 @ 80), (23), NO-OUTDOOR, AUTO-BW
> (5250 - 5350 @ 80), (20), NO-OUTDOOR, AUTO-BW, DFS
> (5470 - 5600 @ 80), (27), DFS
> (5650 - 5730 @ 80), (27), DFS
> (5730 - 5850 @ 80), (36)
> (57000 - 66000 @ 2160), (43), NO-OUTDOOR
>
> If the firmware (or the BDF) is shipped with these rules then there is only
> a 10 MHz overlap with the weather radar:
>
> * below: 5470 - 5590
> * weather radar: 5590 - 5600
> * above: (none for the rule "5470 - 5600 @ 80")
>
> There are several wrong assumption in the ath11k code:
>
> * there is always a valid range below the weather radar
> (actually: there could be no range below the weather radar range OR range
> could be smaller than 20 MHz)
> * intersected range in the weather radar range is valid
> (actually: the range could be smaller than 20 MHz)
> * range above weather radar is either empty or valid
> (actually: the range could be smaller than 20 MHz)
>
> These wrong assumption will lead in this example to a rule
>
> (5590 - 5600 @ 20), (N/A, 27), (600000 ms), DFS, AUTO-BW
>
> which is invalid according to is_valid_reg_rule() because the freq_diff is
> only 10 MHz but the max_bandwidth is set to 20 MHz. Which results in a
> rejection like:
>
> WARNING: at backports-20210222_001-4.4.60-b157d2276/net/wireless/reg.c:3984
> [...]
> Call trace:
> [<ffffffbffc3d2e50>] reg_get_max_bandwidth+0x300/0x3a8 [cfg80211]
> [<ffffffbffc3d3d0c>] regulatory_set_wiphy_regd_sync+0x3c/0x98 [cfg80211]
> [<ffffffbffc651598>] ath11k_regd_update+0x1a8/0x210 [ath11k]
> [<ffffffbffc652108>] ath11k_regd_update_work+0x18/0x20 [ath11k]
> [<ffffffc0000a93e0>] process_one_work+0x1f8/0x340
> [<ffffffc0000a9784>] worker_thread+0x25c/0x448
> [<ffffffc0000aedc8>] kthread+0xd0/0xd8
> [<ffffffc000085550>] ret_from_fork+0x10/0x40
> ath11k c000000.wifi: failed to perform regd update : -22
> Invalid regulatory domain detected
>
> To avoid this, the algorithm has to be changed slightly. Instead of
> splitting a rule which overlaps with the weather radar range into 3 pieces
> and accepting the first two parts blindly, it must actually be checked for
> each piece whether it is a valid range. And only if it is valid, add it to
> the output array.
>
> When these checks are in place, the processed rules for AU would end up as
>
> country AU: DFS-ETSI
> (2400 - 2483 @ 40), (N/A, 36), (N/A)
> (5150 - 5250 @ 80), (6, 23), (N/A), NO-OUTDOOR, AUTO-BW
> (5250 - 5350 @ 80), (6, 20), (0 ms), NO-OUTDOOR, DFS, AUTO-BW
> (5470 - 5590 @ 80), (6, 27), (0 ms), DFS, AUTO-BW
> (5650 - 5730 @ 80), (6, 27), (0 ms), DFS, AUTO-BW
> (5730 - 5850 @ 80), (6, 36), (N/A), AUTO-BW
>
> and will be accepted by the wireless regulatory code.
>
> Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")
> Signed-off-by: Sven Eckelmann <sven@xxxxxxxxxxxxx>
> Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx>
Patch applied to ath-next branch of ath.git, thanks.
086c921a3540 ath11k: Fix ETSI regd with weather radar overlap
--
https://patchwork.kernel.org/project/linux-wireless/patch/20211112153116.1214421-1-sven@xxxxxxxxxxxxx/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
