Re: [PATCH] dmaengine: qcom: bam_dma: fix runtime PM underflow

From: Steev Klimaszewski <steev@kali.org>
To: Caleb Connolly <caleb.connolly@linaro.org>,
	Andy Gross <agross@kernel.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Vinod Koul <vkoul@kernel.org>,
	Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
	linux-arm-msm@vger.kernel.org, dmaengine@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] dmaengine: qcom: bam_dma: fix runtime PM underflow
Date: Sat, 11 Jun 2022 13:19:27 -0500	[thread overview]
Message-ID: <03923830-c3ae-6ef8-890a-361341c18e95@kali.org> (raw)
In-Reply-To: <20220609195043.1544625-1-caleb.connolly@linaro.org>

Hi Caleb,

On 6/9/22 2:50 PM, Caleb Connolly wrote:
> When PM runtime is disabled, pm_runtime_get() isn't called, but
> pm_runtime_put() still is. Fix this by creating a matching wrapper
> on pm_runtime_put_autosuspend().
>
> Fixes: dbad41e7bb5f ("dmaengine: qcom: bam_dma: check if the runtime pm enabled")
> Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
> ---
>   drivers/dma/qcom/bam_dma.c | 18 +++++++++++++-----
>   1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
> index 87f6ca1541cf..a36dedee262e 100644
> --- a/drivers/dma/qcom/bam_dma.c
> +++ b/drivers/dma/qcom/bam_dma.c
> @@ -566,6 +566,14 @@ static int bam_pm_runtime_get_sync(struct device *dev)
>   	return 0;
>   }
>   
> +static int bam_pm_runtime_put_autosuspend(struct device *dev)
> +{
> +	if (pm_runtime_enabled(dev))
> +		return pm_runtime_put_autosuspend(dev);
> +
> +	return 0;
> +}
> +
>   /**
>    * bam_free_chan - Frees dma resources associated with specific channel
>    * @chan: specified channel
> @@ -617,7 +625,7 @@ static void bam_free_chan(struct dma_chan *chan)
>   
>   err:
>   	pm_runtime_mark_last_busy(bdev->dev);
> -	pm_runtime_put_autosuspend(bdev->dev);
> +	bam_pm_runtime_put_autosuspend(bdev->dev);
>   }
>   
>   /**
> @@ -793,7 +801,7 @@ static int bam_pause(struct dma_chan *chan)
>   	bchan->paused = 1;
>   	spin_unlock_irqrestore(&bchan->vc.lock, flag);
>   	pm_runtime_mark_last_busy(bdev->dev);
> -	pm_runtime_put_autosuspend(bdev->dev);
> +	bam_pm_runtime_put_autosuspend(bdev->dev);
>   
>   	return 0;
>   }
> @@ -819,7 +827,7 @@ static int bam_resume(struct dma_chan *chan)
>   	bchan->paused = 0;
>   	spin_unlock_irqrestore(&bchan->vc.lock, flag);
>   	pm_runtime_mark_last_busy(bdev->dev);
> -	pm_runtime_put_autosuspend(bdev->dev);
> +	bam_pm_runtime_put_autosuspend(bdev->dev);
>   
>   	return 0;
>   }
> @@ -936,7 +944,7 @@ static irqreturn_t bam_dma_irq(int irq, void *data)
>   	}
>   
>   	pm_runtime_mark_last_busy(bdev->dev);
> -	pm_runtime_put_autosuspend(bdev->dev);
> +	bam_pm_runtime_put_autosuspend(bdev->dev);
>   
>   	return IRQ_HANDLED;
>   }
> @@ -1111,7 +1119,7 @@ static void bam_start_dma(struct bam_chan *bchan)
>   			bam_addr(bdev, bchan->id, BAM_P_EVNT_REG));
>   
>   	pm_runtime_mark_last_busy(bdev->dev);
> -	pm_runtime_put_autosuspend(bdev->dev);
> +	bam_pm_runtime_put_autosuspend(bdev->dev);
>   }
>   
>   /**

I've tested this patch here and no longer see the logs filling up with 
messages about Runtime PM underflows.  Tested on the Lenovo Yoga C630.

Tested-by: Steev Klimaszewski <steev@kali.org>