[RFC-PATCH] ath9k_htc: Adjust beacon timers for Power Save

[RFC-PATCH] ath9k_htc: Adjust beacon timers for Power Save

[Doru]

From: Doru Gucea <gucea.doru@gmail.com>

Each time we receive a beacon we need to adjust the hardware
timers for next DTIM and next TBTT.

Before this commit, the Power Save behaviour was incorrect.
The scenario was:
- STA receives a beacon from AP with TIM unset;
- mac80211 layers puts the chip to sleep;
- chip is woken up by mac80211's software timer reponsible for
beacon miss after 7 * beacon_interval period.

Normally the chip should sleep at most DTIM period. This commit
configures hardware timers for waking up the chip correctly.

More details on the wiki:
https://github.com/doru91/linux-stable/wiki/Single-Interface-Power-Save

Signed-off-by: Doru Gucea <gucea.doru@gmail.com>
---
 drivers/net/wireless/ath/ath9k/htc_drv_main.c | 4 ++++
 net/mac80211/mlme.c                           | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_main.c b/drivers/net/wireless/ath/ath9k/htc_drv_main.c
index 172a9ff..59a76e0 100644
--- a/drivers/net/wireless/ath/ath9k/htc_drv_main.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_main.c
@@ -1521,6 +1521,10 @@ static void ath9k_htc_bss_info_changed(struct ieee80211_hw *hw,
 	mutex_lock(&priv->mutex);
 	ath9k_htc_ps_wakeup(priv);
 
+	/* adjust beacon timers */
+	if (changed && BSS_CHANGED_BEACON_INFO)
+		ath9k_htc_beacon_config(priv, vif);
+
 	if (changed & BSS_CHANGED_ASSOC) {
 		ath_dbg(common, CONFIG, "BSS Changed ASSOC %d\n",
 			bss_conf->assoc);
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index cd7e55e..ce92a39 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -3536,6 +3536,12 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
 			sdata->vif.bss_conf.sync_dtim_count = 0;
 	}
 
+	/* trigger hardware timers adjustment
+	 * this needs to be done before beacon filtering
+	 */
+	changed |= BSS_CHANGED_BEACON_INFO;
+	ieee80211_bss_info_change_notify(sdata, changed);
+
 	if (ncrc == ifmgd->beacon_crc && ifmgd->beacon_crc_valid)
 		return;
 	ifmgd->beacon_crc = ncrc;
-- 
1.9.1

Re: [RFC-PATCH] ath9k_htc: Adjust beacon timers for Power Save

[Kalle Valo]

Doru <gucea.doru@gmail.com> writes:

> From: Doru Gucea <gucea.doru@gmail.com>
>
> Each time we receive a beacon we need to adjust the hardware
> timers for next DTIM and next TBTT.
>
> Before this commit, the Power Save behaviour was incorrect.
> The scenario was:
> - STA receives a beacon from AP with TIM unset;
> - mac80211 layers puts the chip to sleep;
> - chip is woken up by mac80211's software timer reponsible for
> beacon miss after 7 * beacon_interval period.
>
> Normally the chip should sleep at most DTIM period. This commit
> configures hardware timers for waking up the chip correctly.
>
> More details on the wiki:
> https://github.com/doru91/linux-stable/wiki/Single-Interface-Power-Save
>
> Signed-off-by: Doru Gucea <gucea.doru@gmail.com>
> ---
>  drivers/net/wireless/ath/ath9k/htc_drv_main.c | 4 ++++
>  net/mac80211/mlme.c                           | 6 ++++++
>  2 files changed, 10 insertions(+)

[...]

> --- a/net/mac80211/mlme.c
> +++ b/net/mac80211/mlme.c
> @@ -3536,6 +3536,12 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
>  			sdata->vif.bss_conf.sync_dtim_count = 0;
>  	}
>  
> +	/* trigger hardware timers adjustment
> +	 * this needs to be done before beacon filtering
> +	 */
> +	changed |= BSS_CHANGED_BEACON_INFO;
> +	ieee80211_bss_info_change_notify(sdata, changed);

You shouldn't mix driver and mac80211 changes in the same patch, I
suspect Johannes didn't even notice this change because of that. Create
a new patchset with two patches, one for ath9k and another for mac80211.

-- 
Kalle Valo

Re: [RFC-PATCH] ath9k_htc: Adjust beacon timers for Power Save

[Gucea Doru]

On Wed, Feb 15, 2017 at 11:02 AM, Kalle Valo <kvalo@codeaurora.org> wrote:
> Doru <gucea.doru@gmail.com> writes:
>
>> From: Doru Gucea <gucea.doru@gmail.com>
>>
>> Each time we receive a beacon we need to adjust the hardware
>> timers for next DTIM and next TBTT.
>>
>> Before this commit, the Power Save behaviour was incorrect.
>> The scenario was:
>> - STA receives a beacon from AP with TIM unset;
>> - mac80211 layers puts the chip to sleep;
>> - chip is woken up by mac80211's software timer reponsible for
>> beacon miss after 7 * beacon_interval period.
>>
>> Normally the chip should sleep at most DTIM period. This commit
>> configures hardware timers for waking up the chip correctly.
>>
>> More details on the wiki:
>> https://github.com/doru91/linux-stable/wiki/Single-Interface-Power-Save
>>
>> Signed-off-by: Doru Gucea <gucea.doru@gmail.com>
>> ---
>>  drivers/net/wireless/ath/ath9k/htc_drv_main.c | 4 ++++
>>  net/mac80211/mlme.c                           | 6 ++++++
>>  2 files changed, 10 insertions(+)
>
> [...]
>
>> --- a/net/mac80211/mlme.c
>> +++ b/net/mac80211/mlme.c
>> @@ -3536,6 +3536,12 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
>>                       sdata->vif.bss_conf.sync_dtim_count = 0;
>>       }
>>
>> +     /* trigger hardware timers adjustment
>> +      * this needs to be done before beacon filtering
>> +      */
>> +     changed |= BSS_CHANGED_BEACON_INFO;
>> +     ieee80211_bss_info_change_notify(sdata, changed);
>
> You shouldn't mix driver and mac80211 changes in the same patch, I
> suspect Johannes didn't even notice this change because of that. Create
> a new patchset with two patches, one for ath9k and another for mac80211.

Thanks, I've just sent two patches as you suggested.

>
> --
> Kalle Valo