Re: [PATCH 5/5] drm/msm: Add debugfs to disable hw err handling

[Akhil P Oommen <akhilpo@xxxxxxxxxxxxxx>]

On 11/9/2021 11:41 PM, Rob Clark wrote:
> From: Rob Clark <robdclark@xxxxxxxxxxxx>
>
> Add a debugfs interface to ignore hw error irqs, in order to force
> fallback to sw hangcheck mechanism.  Because the hw error detection is
> pretty good on newer gens, we need this for igt tests to test the sw
> hang detection.
>
> Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
> ---
>   drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 6 ++++++
>   drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 4 ++++
>   drivers/gpu/drm/msm/msm_debugfs.c     | 3 +++
>   drivers/gpu/drm/msm/msm_drv.h         | 9 +++++++++
>   4 files changed, 22 insertions(+)
>
> diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> index 6163990a4d09..ec8e043c9d38 100644
> --- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> @@ -1252,6 +1252,7 @@ static void a5xx_fault_detect_irq(struct msm_gpu *gpu)
>   
>   static irqreturn_t a5xx_irq(struct msm_gpu *gpu)
>   {
> +	struct msm_drm_private *priv = gpu->dev->dev_private;
>   	u32 status = gpu_read(gpu, REG_A5XX_RBBM_INT_0_STATUS);
>   
>   	/*
> @@ -1261,6 +1262,11 @@ static irqreturn_t a5xx_irq(struct msm_gpu *gpu)
>   	gpu_write(gpu, REG_A5XX_RBBM_INT_CLEAR_CMD,
>   		status & ~A5XX_RBBM_INT_0_MASK_RBBM_AHB_ERROR);
>   
> +	if (priv->disable_err_irq) {
> +		status &= A5XX_RBBM_INT_0_MASK_CP_CACHE_FLUSH_TS |
> +			  A5XX_RBBM_INT_0_MASK_CP_SW;
> +	}
> +
>   	/* Pass status to a5xx_rbbm_err_irq because we've already cleared it */
>   	if (status & RBBM_ERROR_MASK)
>   		a5xx_rbbm_err_irq(gpu, status);
> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> index 3d2da81cb2c9..8a2af3a27e33 100644
> --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> @@ -1373,10 +1373,14 @@ static void a6xx_fault_detect_irq(struct msm_gpu *gpu)
>   
>   static irqreturn_t a6xx_irq(struct msm_gpu *gpu)
>   {
> +	struct msm_drm_private *priv = gpu->dev->dev_private;
>   	u32 status = gpu_read(gpu, REG_A6XX_RBBM_INT_0_STATUS);
>   
>   	gpu_write(gpu, REG_A6XX_RBBM_INT_CLEAR_CMD, status);
>   
> +	if (priv->disable_err_irq)
> +		status &= A6XX_RBBM_INT_0_MASK_CP_CACHE_FLUSH_TS;
> +
>   	if (status & A6XX_RBBM_INT_0_MASK_RBBM_HANG_DETECT)
>   		a6xx_fault_detect_irq(gpu);
>   
> diff --git a/drivers/gpu/drm/msm/msm_debugfs.c b/drivers/gpu/drm/msm/msm_debugfs.c
> index 6a99e8b5d25d..956b1efc3721 100644
> --- a/drivers/gpu/drm/msm/msm_debugfs.c
> +++ b/drivers/gpu/drm/msm/msm_debugfs.c
> @@ -242,6 +242,9 @@ void msm_debugfs_init(struct drm_minor *minor)
>   	debugfs_create_u32("hangcheck_period_ms", 0600, minor->debugfs_root,
>   		&priv->hangcheck_period);
>   
> +	debugfs_create_bool("disable_err_irq", 0600, minor->debugfs_root,
> +		&priv->disable_err_irq);
> +
>   	debugfs_create_file("shrink", S_IRWXU, minor->debugfs_root,
>   		dev, &shrink_fops);
>   
> diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
> index 2943c21d9aac..a8da7a7efb84 100644
> --- a/drivers/gpu/drm/msm/msm_drv.h
> +++ b/drivers/gpu/drm/msm/msm_drv.h
> @@ -246,6 +246,15 @@ struct msm_drm_private {
>   
>   	/* For hang detection, in ms */
>   	unsigned int hangcheck_period;
> +
> +	/**
> +	 * disable_err_irq:
> +	 *
> +	 * Disable handling of GPU hw error interrupts, to force fallback to
> +	 * sw hangcheck timer.  Written (via debugfs) by igt tests to test
> +	 * the sw hangcheck mechanism.
> +	 */
> +	bool disable_err_irq;
>   };
>   
>   struct msm_format {

Reviewed-by: Akhil P Oommen <akhilpo@xxxxxxxxxxxxxx>

-Akhil.