Re: [PATCH 3/4] mwifiex: Flag wake-up interrupt as IRQ_NOAUTOEN rather than disabling it too late

From: Brian Norris <briannorris@chromium.org>
To: Marc Zyngier <marc.zyngier@arm.com>
Cc: Amitkumar Karwar <amitkarwar@gmail.com>,
	Enric Balletbo i Serra <enric.balletbo@collabora.com>,
	Ganapathi Bhat <gbhat@marvell.com>,
	Heiko Stuebner <heiko@sntech.de>,
	Kalle Valo <kvalo@codeaurora.org>,
	Nishant Sarmukadam <nishants@marvell.com>,
	Rob Herring <robh+dt@kernel.org>,
	Xinming Hu <huxinming820@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org,
	linux-wireless@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH 3/4] mwifiex: Flag wake-up interrupt as IRQ_NOAUTOEN rather than disabling it too late
Date: Tue, 26 Feb 2019 15:31:31 -0800	[thread overview]
Message-ID: <20190226233130.GB174696@google.com> (raw)
In-Reply-To: <20190224140426.3267-4-marc.zyngier@arm.com>

Hi Marc,

On Sun, Feb 24, 2019 at 02:04:25PM +0000, Marc Zyngier wrote:
> The mwifiex driver makes unsafe assumptions about the state of the
> wake-up interrupt. It requests it and only then disable it. Of
> course, the interrupt may be screaming for whatever reason at that
> time, and the handler will then be called without the interrupt
> having been registered with the PM/wakeup subsystem. Oops.
> 
> The right way to handle this kind of situation is to flag the
> interrupt with IRQ_NOAUTOEN before requesting it. It will then
> stay disabled until someone (the wake-up subsystem) enables it.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

This could be:

Fixes: 853402a00823 ("mwifiex: Enable WoWLAN for both sdio and pcie")

although, that was just borrowing the existing antipattern from SDIO
code..

Reviewed-by: Brian Norris <briannorris@chromium.org>

Thanks.

> ---
>  drivers/net/wireless/marvell/mwifiex/main.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/marvell/mwifiex/main.c b/drivers/net/wireless/marvell/mwifiex/main.c
> index 2105c2b7c627..82cf35e50579 100644
> --- a/drivers/net/wireless/marvell/mwifiex/main.c
> +++ b/drivers/net/wireless/marvell/mwifiex/main.c
> @@ -1610,6 +1610,7 @@ static void mwifiex_probe_of(struct mwifiex_adapter *adapter)
>  			 "wake-up interrupt outside 'wake-up' subnode of %pOF\n",
>  			 adapter->dt_node);
>  
> +	irq_set_status_flags(adapter->irq_wakeup, IRQ_NOAUTOEN);
>  	ret = devm_request_irq(dev, adapter->irq_wakeup,
>  			       mwifiex_irq_wakeup_handler, IRQF_TRIGGER_LOW,
>  			       "wifi_wake", adapter);
> @@ -1619,7 +1620,6 @@ static void mwifiex_probe_of(struct mwifiex_adapter *adapter)
>  		goto err_exit;
>  	}
>  
> -	disable_irq(adapter->irq_wakeup);
>  	if (device_init_wakeup(dev, true)) {
>  		dev_err(dev, "fail to init wakeup for mwifiex\n");
>  		goto err_exit;
> -- 
> 2.20.1
> 