WCN7850: DFS broken since 176f3009ae598d0523b2

[Mihai Moldovan]

Hi


In 176f3009ae598d0523b267db319fe16f69577231[0], radar detect widths were removed 
for single pdev devices, fully disabling DFS on WCN7850.

I do understand that running DFS on two channels simultaneously is (currently?) 
not supported, but this effectively breaks operations on all DFS channels, even 
though only one is being used.


I've tried re-enabling the radar detect widths, but that only lead to an 
ieee80211 subsystem error (which I haven't further debugged) and made the card 
unusable because booting it up failed, which required a full power shutdown of 
the machine to reset it from this broken state (literally disconnecting power 
physically for a few moments).

Setting num_different_channels to 1 for single pdev devices and re-enabling the 
radar detect widths works to re-enable DFS, but naturally that disables MLO.

I'm probably fine with not having MLO capabilities (at least currently), but 
having to modify the source code to get DFS support back certainly isn't ideal.

Are there any plans to fix DFS support for single pdev devices?


Mihai

[0] 
https://patch.msgid.link/20250409-ath12k-wcn7850-mlo-support-v2-9-3801132ca2c3@quicinc.com
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