[Intel-gfx] [RFC] drm/i915: Disable connector polling at runtime suspend

[Imre Deak]

On Fri, Jul 17, 2020 at 05:34:25PM +0530, Anshuman Gupta wrote:
> While i915 device is in runtime suspend, DRM connector polling
> causing device to wakeup from runtime suspend.
> This harm overall cpu idle statistics, therefore
> disabling polling while in runtime suspend.

Before disabling polling we would need to enable hotplug interrupts
during the runtime suspended state. Also I haven't seen yet stats where
polling (which has a 10 sec period) have a significant effect on
idle residencies.

> Cc: Imre Deak <imre.deak at intel.com>
> Signed-off-by: Anshuman Gupta <anshuman.gupta at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 5fd5af4bc855..1229c72f19c9 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1595,6 +1595,8 @@ static int intel_runtime_suspend(struct device *kdev)
>  
>  	disable_rpm_wakeref_asserts(rpm);
>  
> +	drm_kms_helper_poll_disable(&dev_priv->drm);
> +
>  	/*
>  	 * We are safe here against re-faults, since the fault handler takes
>  	 * an RPM reference.
> @@ -1699,6 +1701,8 @@ static int intel_runtime_resume(struct device *kdev)
>  	 */
>  	intel_gt_runtime_resume(&dev_priv->gt);
>  
> +	drm_kms_helper_poll_enable(&dev_priv->drm);
> +
>  	/*
>  	 * On VLV/CHV display interrupts are part of the display
>  	 * power well, so hpd is reinitialized from there. For
> -- 
> 2.26.2
>