Messages in this thread | | | Date | Tue, 10 Jan 2023 16:23:21 +0100 | Subject | Re: ieee80211_handle_wake_tx_queue and dynamic ps regression | From | Alexander Wetzel <> |
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On 10.01.23 15:47, Bryan O'Donoghue wrote: > On 10/01/2023 12:44, Bryan O'Donoghue wrote: >> + linux-wireless >> On 10/01/2023 12:35, Bryan O'Donoghue wrote: >>> commit a790cc3a4fad75048295571a350b95b87e022a5a >>> (wake_tx_queue-broken-23-08-01) >>> Author: Alexander Wetzel <alexander@wetzel-home.de> >>> Date: Sun Oct 9 18:30:39 2022 +0200 >>> >>> wifi: mac80211: add wake_tx_queue callback to drivers >>> >>> is causing a regression with >>> >>> - CONF_PS = 1 >>> - CONF_DYNAMIC_PS = 0 >>> - ieee80211_handle_wake_tx_queue >>> >>> In this case we get stuck in a loop similar to this >>> >>> // IEEE80211_CONF_CHANGE_PS >>> [ 17.255480] wcn36xx: wcn36xx_change_ps/312 enable >>> [ 18.088835] ieee80211_tx_h_dynamic_ps/263 setting >>> IEEE80211_QUEUE_STOP_REASON_PS >>> [ 18.088906] ieee80211_handle_wake_tx_queue/334 entry >>> [ 18.091505] ieee80211_dynamic_ps_disable_work/2250 calling >>> ieee80211_hw_config() >>> [ 18.095370] ieee80211_handle_wake_tx_queue/338 wake_tx_push_queue >>> >>> // IEEE80211_CONF_CHANGE_PS >>> [ 18.102625] wcn36xx: wcn36xx_change_ps/312 disable >>> [ 18.107643] wake_tx_push_queue/303 entry >>> >>> // txq is stopped here reason == IEEE80211_QUEUE_STOP_REASON_PS >>> [ 18.107654] wake_tx_push_queue/311 q_stopped bitmask 0x00000002 >>> IEEE80211_QUEUE_STOP_REASON_PS true >>> [ 18.107661] wake_tx_push_queue/324 exit >>> [ 18.107667] ieee80211_handle_wake_tx_queue/342 exit >>> [ 18.115560] ieee80211_handle_wake_tx_queue/334 entry >>> [ 18.139937] ieee80211_handle_wake_tx_queue/338 wake_tx_push_queue >>> [ 18.145163] wake_tx_push_queue/303 entry >>> [ 18.150016] ieee80211_dynamic_ps_disable_work/2252 completed >>> ieee80211_hw_config() >>> >>> // now we unset IEEE80211_QUEUE_STOP_REASON_PS but too late >>> [ 18.151145] wake_tx_push_queue/311 q_stopped bitmask 0x00000002 >>> IEEE80211_QUEUE_STOP_REASON_PS true >>> [ 18.155263] ieee80211_dynamic_ps_disable_work/2254 clearing >>> IEEE80211_QUEUE_STOP_REASON_PS >>> [ 18.162531] wake_tx_push_queue/324 exit >>> [ 18.162548] ieee80211_handle_wake_tx_queue/342 exit >>> [ 18.183639] ieee80211_dynamic_ps_disable_work/2259 cleared >>> IEEE80211_QUEUE_STOP_REASON_PS >>> >>> // IEEE80211_CONF_CHANGE_PS runs again >>> [ 18.215487] wcn36xx: wcn36xx_change_ps/312 enable >>> >>> We get stuck in that loop. Packets getting transmitted is a rare >>> event, most are dropped. >
I'll need some time digest that... I report back once I get it.
> BTW I considered implementing a wcn36xx specific wake_tx callback - > which maybe should be done anyway. > > I _don't_ see other drivers checking for q_stopped & > IEEE80211_QUEUE_STOP_REASON_PS > > Should they be ? >
No, they should not.
My take is, that this is a bug in mac80211. I submitted patches to fixing that, they have just been accepted:
https://patchwork.kernel.org/project/linux-wireless/patch/20221230121850.218810-1-alexander@wetzel-home.de/
and
https://patchwork.kernel.org/project/linux-wireless/patch/20230106223141.98696-1-alexander@wetzel-home.de/
Can you test if these also help here?
> If they should check IEEE80211_QUEUE_STOP_REASON_PS, then right now, > they don't. If they shouldn't check IEEE80211_QUEUE_STOP_REASON_PS then > neither should the generic replacement ieee80211_handle_wake_tx_queue() > > --- > bod
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