[PATCH v2 2/5] drm/panthor: Be robust against runtime PM resume failures in the suspend path

[Steven Price]

On 28/11/2024 11:02, Boris Brezillon wrote:
> The runtime PM resume operation is not guaranteed to succeed, but if it
> fails, the device should be in a suspended state. Make sure we're robust
> to resume failures in the unplug path.
> 
> v2:
> - Move the bit that belonged in the next commit
> - Drop the panthor_device_unplug() changes
> 
> Signed-off-by: Boris Brezillon <boris.brezillon at collabora.com>

With the comment fix:

Reviewed-by: Steven Price <steven.price at arm.com>

> ---
>  drivers/gpu/drm/panthor/panthor_fw.c  | 14 +++++++++-----
>  drivers/gpu/drm/panthor/panthor_gpu.c |  3 ++-
>  drivers/gpu/drm/panthor/panthor_mmu.c |  3 ++-
>  3 files changed, 13 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panthor/panthor_fw.c b/drivers/gpu/drm/panthor/panthor_fw.c
> index ebf8980ca9a3..f3d3d8fbe13d 100644
> --- a/drivers/gpu/drm/panthor/panthor_fw.c
> +++ b/drivers/gpu/drm/panthor/panthor_fw.c
> @@ -12,6 +12,7 @@
>  #include <linux/iosys-map.h>
>  #include <linux/mutex.h>
>  #include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
>  
>  #include <drm/drm_drv.h>
>  #include <drm/drm_managed.h>
> @@ -1190,11 +1191,13 @@ void panthor_fw_unplug(struct panthor_device *ptdev)
>  
>  	cancel_delayed_work_sync(&ptdev->fw->watchdog.ping_work);
>  
> -	/* Make sure the IRQ handler can be called after that point. */
> -	if (ptdev->fw->irq.irq)
> -		panthor_job_irq_suspend(&ptdev->fw->irq);
> +	if (!IS_ENABLED(CONFIG_PM) || pm_runtime_active(ptdev->base.dev)) {
> +		/* Make sure the IRQ handler can be called after that point. */
> +		if (ptdev->fw->irq.irq)
> +			panthor_job_irq_suspend(&ptdev->fw->irq);
>  
> -	panthor_fw_stop(ptdev);
> +		panthor_fw_stop(ptdev);
> +	}
>  
>  	list_for_each_entry(section, &ptdev->fw->sections, node)
>  		panthor_kernel_bo_destroy(section->mem);
> @@ -1207,7 +1210,8 @@ void panthor_fw_unplug(struct panthor_device *ptdev)
>  	panthor_vm_put(ptdev->fw->vm);
>  	ptdev->fw->vm = NULL;
>  
> -	panthor_gpu_power_off(ptdev, L2, ptdev->gpu_info.l2_present, 20000);
> +	if (!IS_ENABLED(CONFIG_PM) || pm_runtime_active(ptdev->base.dev))
> +		panthor_gpu_power_off(ptdev, L2, ptdev->gpu_info.l2_present, 20000);
>  }
>  
>  /**
> diff --git a/drivers/gpu/drm/panthor/panthor_gpu.c b/drivers/gpu/drm/panthor/panthor_gpu.c
> index 0f3cac6ec88e..ee85a371bc38 100644
> --- a/drivers/gpu/drm/panthor/panthor_gpu.c
> +++ b/drivers/gpu/drm/panthor/panthor_gpu.c
> @@ -180,7 +180,8 @@ void panthor_gpu_unplug(struct panthor_device *ptdev)
>  	unsigned long flags;
>  
>  	/* Make sure the IRQ handler is not running after that point. */
> -	panthor_gpu_irq_suspend(&ptdev->gpu->irq);
> +	if (!IS_ENABLED(CONFIG_PM) || pm_runtime_active(ptdev->base.dev))
> +		panthor_gpu_irq_suspend(&ptdev->gpu->irq);
>  
>  	/* Wake-up all waiters. */
>  	spin_lock_irqsave(&ptdev->gpu->reqs_lock, flags);
> diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c
> index 9478ee2093d1..6716463903bc 100644
> --- a/drivers/gpu/drm/panthor/panthor_mmu.c
> +++ b/drivers/gpu/drm/panthor/panthor_mmu.c
> @@ -2681,7 +2681,8 @@ int panthor_vm_prepare_mapped_bos_resvs(struct drm_exec *exec, struct panthor_vm
>   */
>  void panthor_mmu_unplug(struct panthor_device *ptdev)
>  {
> -	panthor_mmu_irq_suspend(&ptdev->mmu->irq);
> +	if (!IS_ENABLED(CONFIG_PM) || pm_runtime_active(ptdev->base.dev))
> +		panthor_mmu_irq_suspend(&ptdev->mmu->irq);
>  
>  	mutex_lock(&ptdev->mmu->as.slots_lock);
>  	for (u32 i = 0; i < ARRAY_SIZE(ptdev->mmu->as.slots); i++) {