Re: [PATCH] drm/imagination: retry runtime idle when firmware is not yet idle

[Troy Mitchell]

Hi Baihui,

On Thu Oct 29, 2026 at 4:38 PM +0800, Baihui Liang wrote:
> Returning -EBUSY from ->runtime_idle() prevents the PM core from
> retrying the idle check. Schedule an autosuspend so the idle state
> can be re-evaluated once the firmware reaches ROGUE_FWIF_POW_IDLE.
>
> Signed-off-by: Baihui Liang <liangbaihui@xxxxxxxxxxxxxxxxxx>
> ---
> Tested on SpacemiT K3 (PowerVR Rogue BXM-4-64) by running vulkaninfo
> repeatedly. Without this change the device intermittently stayed
> runtime-active after the last user went away, because the firmware had
> not yet reached ROGUE_FWIF_POW_IDLE when the idle check ran. With the
> change the device reliably suspends.
> ---
>  drivers/gpu/drm/imagination/pvr_power.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/imagination/pvr_power.c b/drivers/gpu/drm/imagination/pvr_power.c
> index eb4b6ecdf4f..6f38249ffcb 100644
> --- a/drivers/gpu/drm/imagination/pvr_power.c
> +++ b/drivers/gpu/drm/imagination/pvr_power.c
> @@ -434,7 +434,16 @@ pvr_power_device_idle(struct device *dev)
>  	struct drm_device *drm_dev = platform_get_drvdata(plat_dev);
>  	struct pvr_device *pvr_dev = to_pvr_device(drm_dev);
>  
> -	return pvr_power_is_idle(pvr_dev) ? 0 : -EBUSY;
> +	if (pvr_power_is_idle(pvr_dev))
> +		return 0;
> +
> +	/*
> +	 * Firmware not yet idle; reject but schedule autosuspend so
> +	 * runtime_idle() can be retried.
> +	 */
> +	pm_runtime_autosuspend(dev);

If I read the PM core correctly, when this autosuspend timer fires it
calls ->runtime_suspend() directly rather than retrying
->runtime_idle(), so this looks equivalent to returning 0. Could the
real issue be the pm_runtime_put() in pvr_watchdog_worker(), which
perhaps should be pm_runtime_put_autosuspend()?

> +
> +	return -EBUSY;
>  }
>  
>  static int

-- 
Troy Mitchell

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