[PATCH] wcn36xx: Fix packet drop on resume

[PATCH] wcn36xx: Fix packet drop on resume

[Loic Poulain]

If the system is resumed because of an incoming packet, the wcn36xx RX
interrupts is fired before actual resuming of the wireless/mac80211
stack, causing any received packets to be simply dropped. E.g. a ping
request causes a system resume, but is dropped and so never forwarded
to the IP stack.

This change fixes that, disabling DMA interrupts on suspend to no pass
packets until mac80211 is resumed and ready to handle them.

Note that it's not incompatible with RX irq wake.

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
---
 drivers/net/wireless/ath/wcn36xx/main.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/net/wireless/ath/wcn36xx/main.c b/drivers/net/wireless/ath/wcn36xx/main.c
index a42eae6..a650b9e 100644
--- a/drivers/net/wireless/ath/wcn36xx/main.c
+++ b/drivers/net/wireless/ath/wcn36xx/main.c
@@ -1137,6 +1137,13 @@ static int wcn36xx_suspend(struct ieee80211_hw *hw, struct cfg80211_wowlan *wow)
 			goto out;
 		ret = wcn36xx_smd_wlan_host_suspend_ind(wcn);
 	}
+
+	/* Disable IRQ, we don't want to handle any packet before mac80211 is
+	 * resumed and ready to receive packets.
+	 */
+	disable_irq(wcn->tx_irq);
+	disable_irq(wcn->rx_irq);
+
 out:
 	mutex_unlock(&wcn->conf_mutex);
 	return ret;
@@ -1159,6 +1166,10 @@ static int wcn36xx_resume(struct ieee80211_hw *hw)
 		wcn36xx_smd_ipv6_ns_offload(wcn, vif, false);
 		wcn36xx_smd_arp_offload(wcn, vif, false);
 	}
+
+	enable_irq(wcn->tx_irq);
+	enable_irq(wcn->rx_irq);
+
 	mutex_unlock(&wcn->conf_mutex);
 
 	return 0;
-- 
2.7.4

Re: [PATCH] wcn36xx: Fix packet drop on resume

[Bryan O'Donoghue]

On 25/10/2021 09:28, Loic Poulain wrote:
> If the system is resumed because of an incoming packet, the wcn36xx RX
> interrupts is fired before actual resuming of the wireless/mac80211
> stack, causing any received packets to be simply dropped. E.g. a ping
> request causes a system resume, but is dropped and so never forwarded
> to the IP stack.
> 
> This change fixes that, disabling DMA interrupts on suspend to no pass
> packets until mac80211 is resumed and ready to handle them.
> 
> Note that it's not incompatible with RX irq wake.
> 
> Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
> ---
>   drivers/net/wireless/ath/wcn36xx/main.c | 11 +++++++++++
>   1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/net/wireless/ath/wcn36xx/main.c b/drivers/net/wireless/ath/wcn36xx/main.c
> index a42eae6..a650b9e 100644
> --- a/drivers/net/wireless/ath/wcn36xx/main.c
> +++ b/drivers/net/wireless/ath/wcn36xx/main.c
> @@ -1137,6 +1137,13 @@ static int wcn36xx_suspend(struct ieee80211_hw *hw, struct cfg80211_wowlan *wow)
>   			goto out;
>   		ret = wcn36xx_smd_wlan_host_suspend_ind(wcn);
>   	}
> +
> +	/* Disable IRQ, we don't want to handle any packet before mac80211 is
> +	 * resumed and ready to receive packets.
> +	 */
> +	disable_irq(wcn->tx_irq);
> +	disable_irq(wcn->rx_irq);
> +
>   out:
>   	mutex_unlock(&wcn->conf_mutex);
>   	return ret;
> @@ -1159,6 +1166,10 @@ static int wcn36xx_resume(struct ieee80211_hw *hw)
>   		wcn36xx_smd_ipv6_ns_offload(wcn, vif, false);
>   		wcn36xx_smd_arp_offload(wcn, vif, false);
>   	}
> +
> +	enable_irq(wcn->tx_irq);
> +	enable_irq(wcn->rx_irq);
> +
>   	mutex_unlock(&wcn->conf_mutex);
>   
>   	return 0;
> 

LGTM

Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>

Re: [PATCH] wcn36xx: Fix packet drop on resume

[Kalle Valo]

Loic Poulain <loic.poulain@linaro.org> wrote:

> If the system is resumed because of an incoming packet, the wcn36xx RX
> interrupts is fired before actual resuming of the wireless/mac80211
> stack, causing any received packets to be simply dropped. E.g. a ping
> request causes a system resume, but is dropped and so never forwarded
> to the IP stack.
> 
> This change fixes that, disabling DMA interrupts on suspend to no pass
> packets until mac80211 is resumed and ready to handle them.
> 
> Note that it's not incompatible with RX irq wake.
> 
> Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
> Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
> Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

Patch applied to ath-next branch of ath.git, thanks.

df0697801d8a wcn36xx: Fix packet drop on resume

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/1635150496-19290-1-git-send-email-loic.poulain@linaro.org/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches