On 29/09/2026 04:44, Adrián Larumbe wrote:
> This will be of great help when testing potential races between the GPU
> reset sequence and other parts of the code accessing HW registers.
> 
> We must also disable the reset work item rather than simply cancelling
> it, to prevent the knob from triggering another reset when the device
> is being removed.
> 
> Reviewed-by: Boris Brezillon <[email protected]>
> Signed-off-by: Adrián Larumbe <[email protected]>
> ---
>  drivers/gpu/drm/panfrost/panfrost_device.c | 42 
> ++++++++++++++++++++++++++++++
>  drivers/gpu/drm/panfrost/panfrost_job.c    |  2 +-
>  2 files changed, 43 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_device.c 
> b/drivers/gpu/drm/panfrost/panfrost_device.c
> index 09a5752a3f40..94d2de341838 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_device.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_device.c
> @@ -2,6 +2,7 @@
>  /* Copyright 2018 Marty E. Plummer <[email protected]> */
>  /* Copyright 2019 Linaro, Ltd, Rob Herring <[email protected]> */
>  
> +#include <linux/debugfs.h>
>  #include <linux/clk.h>
>  #include <linux/reset.h>
>  #include <linux/platform_device.h>
> @@ -595,9 +596,50 @@ EXPORT_GPL_DEV_PM_OPS(panfrost_pm_ops) = {
>  };
>  
>  #ifdef CONFIG_DEBUG_FS
> +static int reset_get(void *data, u64 *val)
> +{
> +     struct panfrost_device *pfdev =
> +             container_of(data, struct panfrost_device, base);
> +
> +     *val = atomic_read(&pfdev->reset.pending);
> +     return 0;
> +}
> +
> +static int reset_set(void *data, u64 val)
> +{
> +     struct panfrost_device *pfdev =
> +             container_of(data, struct panfrost_device, base);
> +     int ret = pm_runtime_get_if_active(pfdev->base.dev);
> +
> +     if (!ret)
> +             return 0;
> +
> +     panfrost_device_schedule_reset(pfdev);
> +     flush_work(&pfdev->reset.work);
> +
> +     /* ret < 0 means runtime PM for the device is disabled, so we
> +      * only need to return the PM reference in the opposite case
> +      */
> +     if (ret > 0)
> +             pm_runtime_put(pfdev->base.dev);
> +
> +     return 0;
> +}

NIT: If this wasn't debugfs I'd be complaining that you're ignoring
'val' and so this isn't very extensible. But hey, it's debugfs... so:

Reviewed-by: Steven Price <[email protected]>

> +
> +DEFINE_DEBUGFS_ATTRIBUTE(panfrost_reset_debugfs_fops,
> +                      reset_get, reset_set,
> +                      "0x%08llx\n");
> +
> +static void panfrost_reset_debugfs_init(struct drm_minor *minor)
> +{
> +     debugfs_create_file("reset", 0600, minor->debugfs_root,
> +                         minor->dev, &panfrost_reset_debugfs_fops);
> +}
> +
>  void panfrost_device_debugfs_init(struct drm_minor *minor)
>  {
>       panfrost_gem_debugfs_init(minor);
>       panfrost_sched_debugfs_init(minor);
> +     panfrost_reset_debugfs_init(minor);
>  }
>  #endif // CONFIG_DEBUG_FS
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c 
> b/drivers/gpu/drm/panfrost/panfrost_job.c
> index 00fb36c577df..ab65786bf63b 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> @@ -932,7 +932,7 @@ void panfrost_jm_fini(struct panfrost_device *pfdev)
>               drm_sched_fini(&js->queue[j].sched);
>       }
>  
> -     cancel_work_sync(&pfdev->reset.work);
> +     disable_work_sync(&pfdev->reset.work);
>       destroy_workqueue(pfdev->reset.wq);
>  }
>  
> 

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