Re: [PATCH v2 10/11] drm/panthor: Use the irqsave variant of spin_lock in panthor_gpu_irq_handler()

[Steven Price <steven.price@arm.com>]

On 12/05/2026 12:37, Boris Brezillon wrote:
> This is not a bug per-se, because this lock is never taken in an
> interrupt context, but it's not consistent with the other users of this
> lock. We're also planning on transitioning GPU event processing to
> a hard handler. Again, this alone wouldn't justify using the IRQ-safe
> variant, because then this _lock/unlock sequence would be in the
> hard-IRQ path, where IRQs are already disabled, but let's do it anyway,
> to keep things consistent.
> 
> While at it, transition to a guard() instead of a plain lock/unlock
> sequence.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>

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

Although this now leaves the lock in panthor_pwr_irq_handler() the odd
one out...

Thanks,
Steve

> ---
>  drivers/gpu/drm/panthor/panthor_gpu.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panthor/panthor_gpu.c b/drivers/gpu/drm/panthor/panthor_gpu.c
> index d0be758ea3e1..b9c51f8a051d 100644
> --- a/drivers/gpu/drm/panthor/panthor_gpu.c
> +++ b/drivers/gpu/drm/panthor/panthor_gpu.c
> @@ -110,12 +110,11 @@ static void panthor_gpu_irq_handler(struct panthor_irq *pirq, u32 status)
>  	if (status & GPU_IRQ_PROTM_FAULT)
>  		drm_warn(&ptdev->base, "GPU Fault in protected mode\n");
>  
> -	spin_lock(&ptdev->gpu->reqs_lock);
> +	guard(spinlock_irqsave)(&ptdev->gpu->reqs_lock);
>  	if (status & ptdev->gpu->pending_reqs) {
>  		ptdev->gpu->pending_reqs &= ~status;
>  		wake_up_all(&ptdev->gpu->reqs_acked);
>  	}
> -	spin_unlock(&ptdev->gpu->reqs_lock);
>  }
>  
>  static irqreturn_t panthor_gpu_irq_threaded_handler(int irq, void *data)
>