[PATCH] wifi: ath10k: Fix unbalanced IRQ enabling

[Jeff Johnson]

On 5/22/2025 5:09 AM, Loic Poulain wrote:
> When the firmware goes down, both RECOVERY and CRASH_FLUSH flags are set,
> triggering a full recovery sequence once the firmware is back up. This
> includes stopping and restarting the SNOC interface.
> 
> However, this sequence leads to an Unbalanced IRQ warning:
> 
> ------------[ cut here ]------------
> Unbalanced enable for IRQ 112
> WARNING: CPU: 2 PID: 120 at kernel/irq/manage.c:792 __enable_irq+0x4c/0x7c
> CPU: 2 UID: 0 PID: 120 Comm: kworker/2:4 Not tainted [...] #234 PREEMPT
> Hardware name: Qualcomm Technologies, Inc. Robotics RB1 (DT)
> Workqueue: events_freezable ieee80211_restart_work
> pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> pc : __enable_irq+0x4c/0x7c
> lr : __enable_irq+0x4c/0x7c
> sp : ffff800081b3bab0
> [...]
> Call trace:
>  __enable_irq+0x4c/0x7c (P)
>  enable_irq+0x48/0x9c
>  ath10k_snoc_hif_start+0x6c/0x13c
>  ath10k_core_start+0x360/0x1344
>  ath10k_start+0x100/0x8fc
>  drv_start+0x34/0x58
>  ieee80211_reconfig+0xf4/0xfc0
>  ieee80211_restart_work+0x110/0x17c
>  process_one_work+0x150/0x294
>  worker_thread+0x2dc/0x3dc
>  kthread+0x130/0x204
>  ret_from_fork+0x10/0x20
> ---

this causes git to chop the description at this point, which also chops the
tags, so remove it.

> 
> This can be reproduced by restarting rmtfs or triggering remoteproc restart
> via sysfs.
> 
> The root cause is that IRQs are not disabled during SNOC stop in recovery
> scenarios, but are unconditionally re-enabled during SNOC start, leading to
> an imbalance.
> 
> Fix this by skipping IRQ re-enablement in `ath10k_snoc_hif_start()` if a
> firmware recovery is in progress, restoring IRQ state symmetry.
> 
> Fixes: 0e622f67e041 ("ath10k: add support for WCN3990 firmware crash recovery")
> Signed-off-by: Loic Poulain <loic.poulain at oss.qualcomm.com>
> ---
>  drivers/net/wireless/ath/ath10k/snoc.c | 3 ++-

My Qualcomm copyright checker flags:
* drivers/net/wireless/ath/ath10k/snoc.c no QuIC copyright

>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/ath/ath10k/snoc.c b/drivers/net/wireless/ath/ath10k/snoc.c
> index 866bad2db334..e15e1ab30458 100644
> --- a/drivers/net/wireless/ath/ath10k/snoc.c
> +++ b/drivers/net/wireless/ath/ath10k/snoc.c
> @@ -937,7 +937,8 @@ static int ath10k_snoc_hif_start(struct ath10k *ar)
>  
>  	dev_set_threaded(ar->napi_dev, true);
>  	ath10k_core_napi_enable(ar);
> -	ath10k_snoc_irq_enable(ar);
> +	if (!test_bit(ATH10K_SNOC_FLAG_RECOVERY, &ar_snoc->flags))
> +		ath10k_snoc_irq_enable(ar);
>  	ath10k_snoc_rx_post(ar);
>  
>  	clear_bit(ATH10K_SNOC_FLAG_RECOVERY, &ar_snoc->flags);