Re: [PATCH v5 02/11] drm/panfrost: Prevent division by 0

[Boris Brezillon <boris.brezillon@collabora.com>]

On Tue, 11 Aug 2026 22:42:11 +0100
Adrián Larumbe <adrian.larumbe@collabora.com> wrote:

> When updating and debug-printing devfreq stats, in the very unlikely
> off-chance that total device time is less than 100 ns, division by 0
> would happen. Fix the divisor when relevant and rearrange operands.
> 
> Reported-by: Claude <noreply@anthropic.com>
> Closes: https://gitlab.freedesktop.org/panfrost/linux/-/work_items/88
> Fixes: f3ba91228e8e ("drm/panfrost: Add initial panfrost driver")
> Reviewed-by: Steven Price <steven.price@arm.com>
> Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>

Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>

> ---
>  drivers/gpu/drm/panfrost/panfrost_devfreq.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_devfreq.c b/drivers/gpu/drm/panfrost/panfrost_devfreq.c
> index b51c30778811..0fe81d259274 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_devfreq.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_devfreq.c
> @@ -78,7 +78,7 @@ static int panfrost_devfreq_get_dev_status(struct device *dev,
>  
>  	dev_dbg(pfdev->base.dev, "busy %lu total %lu %lu %% freq %lu MHz\n",
>  		status->busy_time, status->total_time,
> -		status->busy_time / (status->total_time / 100),
> +		status->busy_time * 100 / MAX(status->total_time, 1),
>  		status->current_frequency / 1000 / 1000);
>  
>  	return 0;
>