On Wed, Aug 26, 2026 at 04:56:01PM +0200, Boris Brezillon wrote:
> disable/enable_work() provide a ready to use mechanism to temporarily
> disable a work item, so use that instead of the complex state machinery
> based on the PM state.
> 
> This also allows us to automate the reset resubmission in case a reset
> was received while the work item was disabled.
> 
> Signed-off-by: Boris Brezillon <[email protected]>

Reviewed-by: Liviu Dudau <[email protected]>

Best regards,
Liviu

> ---
>  drivers/gpu/drm/panthor/panthor_device.c | 36 
> +++++++++++++++++++++++++-------
>  drivers/gpu/drm/panthor/panthor_device.h |  3 +--
>  2 files changed, 29 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panthor/panthor_device.c 
> b/drivers/gpu/drm/panthor/panthor_device.c
> index 7c55d0c45cfd..2974f4bc0bb1 100644
> --- a/drivers/gpu/drm/panthor/panthor_device.c
> +++ b/drivers/gpu/drm/panthor/panthor_device.c
> @@ -181,6 +181,15 @@ static void panthor_device_free_page(struct drm_device 
> *ddev, void *data)
>       __free_page(data);
>  }
>  
> +static void enable_resets(struct panthor_device *ptdev)
> +{
> +     /* If a reset has been queued while the work was
> +      * disabled, reschedule it.
> +      */
> +     if (enable_work(&ptdev->reset.work) && 
> atomic_read(&ptdev->reset.pending))
> +             queue_work(ptdev->reset.wq, &ptdev->reset.work);
> +}
> +
>  int panthor_device_init(struct panthor_device *ptdev)
>  {
>       u32 *dummy_page_virt;
> @@ -256,6 +265,13 @@ int panthor_device_init(struct panthor_device *ptdev)
>  
>       ptdev->phys_addr = res->start;
>  
> +     /* panthor_device_resume() calls enable_resets(), so we need to disable
> +      * the reset.work manually before this gets called to keep things
> +      * balanced. We don't bother re-enabling the work if the resume fails,
> +      * because the whole initialization will fail in that case, and the work
> +      * will vanish.
> +      */
> +     disable_work(&ptdev->reset.work);
>       ret = devm_pm_runtime_enable(ptdev->base.dev);
>       if (ret)
>               return ret;
> @@ -305,9 +321,6 @@ int panthor_device_init(struct panthor_device *ptdev)
>  
>       panthor_gem_init(ptdev);
>  
> -     /* Now that everything is initialized, we can enable the reset work. */
> -     enable_work(&ptdev->reset.work);
> -
>       /* ~3 frames */
>       pm_runtime_set_autosuspend_delay(ptdev->base.dev, 50);
>       pm_runtime_use_autosuspend(ptdev->base.dev);
> @@ -316,6 +329,9 @@ int panthor_device_init(struct panthor_device *ptdev)
>       if (ret)
>               goto err_disable_autosuspend;
>  
> +     /* Now that everything is initialized, we can enable the reset work. */
> +     enable_resets(ptdev);
> +
>       pm_runtime_put_autosuspend(ptdev->base.dev);
>       return 0;
>  
> @@ -534,10 +550,8 @@ int panthor_device_resume(struct device *dev)
>               /* If there was a reset pending at the time we suspended the
>                * device, we force a slow reset.
>                */
> -             if (atomic_read(&ptdev->reset.pending)) {
> +             if (atomic_cmpxchg(&ptdev->reset.pending, 1, 0))
>                       ptdev->reset.fast = false;
> -                     atomic_set(&ptdev->reset.pending, 0);
> -             }
>  
>               ret = panthor_device_resume_hw_components(ptdev);
>               if (ret && ptdev->reset.fast) {
> @@ -565,6 +579,9 @@ int panthor_device_resume(struct device *dev)
>                           DRM_PANTHOR_USER_MMIO_OFFSET, 0, 1);
>       atomic_set(&ptdev->pm.state, PANTHOR_DEVICE_PM_STATE_ACTIVE);
>       mutex_unlock(&ptdev->pm.mmio_lock);
> +
> +     /* Now that everything is resumed, we can re-enable the reset work. */
> +     enable_resets(ptdev);
>       return 0;
>  
>  err_suspend_devfreq:
> @@ -604,10 +621,13 @@ int panthor_device_suspend(struct device *dev)
>                           DRM_PANTHOR_USER_MMIO_OFFSET, 0, 1);
>       mutex_unlock(&ptdev->pm.mmio_lock);
>  
> +     /* Make sure we're not interrupted by resets after that point
> +      * until the GPU is resumed.
> +      */
> +     disable_work_sync(&ptdev->reset.work);
> +
>       if (panthor_device_is_initialized(ptdev) &&
>           drm_dev_enter(&ptdev->base, &cookie)) {
> -             cancel_work_sync(&ptdev->reset.work);
> -
>               /* We prepare everything as if we were resetting the GPU.
>                * The end of the reset will happen in the resume path though.
>                */
> diff --git a/drivers/gpu/drm/panthor/panthor_device.h 
> b/drivers/gpu/drm/panthor/panthor_device.h
> index 6529e01e838d..f55baa21b25e 100644
> --- a/drivers/gpu/drm/panthor/panthor_device.h
> +++ b/drivers/gpu/drm/panthor/panthor_device.h
> @@ -389,8 +389,7 @@ void panthor_device_unplug(struct panthor_device *ptdev);
>   */
>  static inline void panthor_device_schedule_reset(struct panthor_device 
> *ptdev)
>  {
> -     if (!atomic_cmpxchg(&ptdev->reset.pending, 0, 1) &&
> -         atomic_read(&ptdev->pm.state) == PANTHOR_DEVICE_PM_STATE_ACTIVE)
> +     if (!atomic_cmpxchg(&ptdev->reset.pending, 0, 1))
>               queue_work(ptdev->reset.wq, &ptdev->reset.work);
>  }
>  
> 
> -- 
> 2.55.0
> 

-- 
====================
| I would like to |
| fix the world,  |
| but they're not |
| giving me the   |
 \ source code!  /
  ---------------
    ¯\_(ツ)_/¯

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