[PATCH 1/2] drm/xe: Separate the d3cold and non-d3cold runtime PM handling

[Cavitt, Jonathan]

-----Original Message-----
From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Imre Deak
Sent: Monday, October 7, 2024 7:06 AM
To: intel-xe at lists.freedesktop.org; intel-gfx at lists.freedesktop.org
Cc: Vivi, Rodrigo <rodrigo.vivi at intel.com>
Subject: [PATCH 1/2] drm/xe: Separate the d3cold and non-d3cold runtime PM handling
> 
> For clarity separate the d3cold and non-d3cold runtime PM handling. The
> only change in behavior is disabling polling later during runtime
> resume. This shouldn't make a difference, since the poll disabling is
> handled from a work, which could run at any point wrt. the runtime
> resume handler. The work will also require a runtime PM reference,
> syncing it with the resume handler.
> 
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Signed-off-by: Imre Deak <imre.deak at intel.com>

It seems a bit weird to me that we're enabling hpd polling during the suspend
path and disabling it during the resume path, especially given the second patch's
commit message mentioning that HPD interrupts are getting disabled in the
suspend path.  However, I just looked, and it seems like this is the way it has been
since the beginning, so I'm going to trust that it's supposed to be this way.

Reviewed-by: Jonathan Cavitt <jonathan.cavitt at intel.com>
-Jonathan Cavitt

> ---
>  drivers/gpu/drm/xe/display/xe_display.c | 19 ++++++++++++++-----
>  1 file changed, 14 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/display/xe_display.c b/drivers/gpu/drm/xe/display/xe_display.c
> index ca00a365080fb..cb2449b7921ac 100644
> --- a/drivers/gpu/drm/xe/display/xe_display.c
> +++ b/drivers/gpu/drm/xe/display/xe_display.c
> @@ -345,6 +345,9 @@ static void __xe_display_pm_suspend(struct xe_device *xe, bool runtime)
>  	intel_opregion_suspend(display, s2idle ? PCI_D1 : PCI_D3cold);
>  
>  	intel_dmc_suspend(display);
> +
> +	if (runtime && has_display(xe))
> +		intel_hpd_poll_enable(xe);
>  }
>  
>  void xe_display_pm_suspend(struct xe_device *xe)
> @@ -387,8 +390,10 @@ void xe_display_pm_runtime_suspend(struct xe_device *xe)
>  	if (!xe->info.probe_display)
>  		return;
>  
> -	if (xe->d3cold.allowed)
> +	if (xe->d3cold.allowed) {
>  		__xe_display_pm_suspend(xe, true);
> +		return;
> +	}
>  
>  	intel_hpd_poll_enable(xe);
>  }
> @@ -453,9 +458,11 @@ static void __xe_display_pm_resume(struct xe_device *xe, bool runtime)
>  		intel_display_driver_resume(xe);
>  		drm_kms_helper_poll_enable(&xe->drm);
>  		intel_display_driver_enable_user_access(xe);
> -		intel_hpd_poll_disable(xe);
>  	}
>  
> +	if (has_display(xe))
> +		intel_hpd_poll_disable(xe);
> +
>  	intel_opregion_resume(display);
>  
>  	if (!runtime)
> @@ -474,10 +481,12 @@ void xe_display_pm_runtime_resume(struct xe_device *xe)
>  	if (!xe->info.probe_display)
>  		return;
>  
> -	intel_hpd_poll_disable(xe);
> -
> -	if (xe->d3cold.allowed)
> +	if (xe->d3cold.allowed) {
>  		__xe_display_pm_resume(xe, true);
> +		return;
> +	}
> +
> +	intel_hpd_poll_disable(xe);
>  }
>  
>  
> -- 
> 2.44.2
> 
>