linux-kernel - Re: [PATCH 1/3] remoteproc: qcom_q6v5: Avoid disabling handover IRQ twice

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Message-ID: <czaabkgp3aerp7fntqnpwgilipnum5vmdwwrkem5mugcs7vvd3@q2mwq6ijfbmt>
Date: Tue, 19 Aug 2025 14:44:26 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Stephan Gerhold <stephan.gerhold@...aro.org>
Cc: Bjorn Andersson <andersson@...nel.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Sibi Sankar <quic_sibis@...cinc.com>, Abel Vesa <abel.vesa@...aro.org>,
        linux-arm-msm@...r.kernel.org, linux-remoteproc@...r.kernel.org,
        linux-kernel@...r.kernel.org, Konrad Dybcio <konradybcio@...nel.org>
Subject: Re: [PATCH 1/3] remoteproc: qcom_q6v5: Avoid disabling handover IRQ
 twice

On Tue, Aug 19, 2025 at 01:08:02PM +0200, Stephan Gerhold wrote:
> enable_irq() and disable_irq() are reference counted, so we must make sure
> that each enable_irq() is always paired with a single disable_irq(). If we
> call disable_irq() twice followed by just a single enable_irq(), the IRQ
> will remain disabled forever.
> 
> For the error handling path in qcom_q6v5_wait_for_start(), disable_irq()
> will end up being called twice, because disable_irq() also happens in
> qcom_q6v5_unprepare() when rolling back the call to qcom_q6v5_prepare().
> 
> Fix this by dropping disable_irq() in qcom_q6v5_wait_for_start(). Since
> qcom_q6v5_prepare() is the function that calls enable_irq(), it makes more
> sense to have the rollback handled always by qcom_q6v5_unprepare().
> 
> Fixes: 3b415c8fb263 ("remoteproc: q6v5: Extract common resource handling")

Didn't earlier versions also have the same behaviour?

> Signed-off-by: Stephan Gerhold <stephan.gerhold@...aro.org>
> ---
>  drivers/remoteproc/qcom_q6v5.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/drivers/remoteproc/qcom_q6v5.c b/drivers/remoteproc/qcom_q6v5.c
> index 4ee5e67a9f03f5f766f04396b9a3e45f77293764..769c6d6d6a731672eca9f960b05c68f6d4d77af2 100644
> --- a/drivers/remoteproc/qcom_q6v5.c
> +++ b/drivers/remoteproc/qcom_q6v5.c
> @@ -156,9 +156,6 @@ int qcom_q6v5_wait_for_start(struct qcom_q6v5 *q6v5, int timeout)
>  	int ret;
>  
>  	ret = wait_for_completion_timeout(&q6v5->start_done, timeout);
> -	if (!ret)
> -		disable_irq(q6v5->handover_irq);
> -
>  	return !ret ? -ETIMEDOUT : 0;
>  }
>  EXPORT_SYMBOL_GPL(qcom_q6v5_wait_for_start);
> 
> -- 
> 2.50.1
> 

-- 
With best wishes
Dmitry