[PATCH v3 2/4] drm/i915/display: don't allow DMC wakelock on older hardware

[Shankar, Uma]

> -----Original Message-----
> From: Coelho, Luciano <luciano.coelho at intel.com>
> Sent: Monday, March 18, 2024 7:08 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: intel-xe at lists.freedesktop.org; Shankar, Uma <uma.shankar at intel.com>;
> ville.syrjala at linux.intel.com; Nikula, Jani <jani.nikula at intel.com>
> Subject: [PATCH v3 2/4] drm/i915/display: don't allow DMC wakelock on older
> hardware
> 
> Only allow running DMC wakelock code if the display version is 20 or greater.

One for previous one, don't do intel_dmc_wl_init unconditionally but protect it with
Platform check.

> Signed-off-by: Luca Coelho <luciano.coelho at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dmc_wl.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dmc_wl.c
> b/drivers/gpu/drm/i915/display/intel_dmc_wl.c
> index 5c3d8204ae7e..7c991e22c616 100644
> --- a/drivers/gpu/drm/i915/display/intel_dmc_wl.c
> +++ b/drivers/gpu/drm/i915/display/intel_dmc_wl.c
> @@ -120,6 +120,9 @@ void intel_dmc_wl_enable(struct drm_i915_private
> *i915)
>  	struct intel_dmc_wl *wl = &i915->display.wl;
>  	unsigned long flags;
> 
> +	if (DISPLAY_VER(i915) < 20)
> +		return;
> +
>  	spin_lock_irqsave(&wl->lock, flags);
> 
>  	if (wl->enabled)
> @@ -143,6 +146,9 @@ void intel_dmc_wl_disable(struct drm_i915_private
> *i915)
>  	struct intel_dmc_wl *wl = &i915->display.wl;
>  	unsigned long flags;
> 
> +	if (DISPLAY_VER(i915) < 20)
> +		return;

There can be case where DMC is not loaded, address that as well.
We should not do wakelock in that case.

>  	flush_delayed_work(&wl->work);
> 
>  	spin_lock_irqsave(&wl->lock, flags);
> @@ -171,6 +177,9 @@ void intel_dmc_wl_get(struct drm_i915_private *i915,
> i915_reg_t reg)
>  	struct intel_dmc_wl *wl = &i915->display.wl;
>  	unsigned long flags;
> 
> +	if (DISPLAY_VER(i915) < 20)
> +		return;
> +
>  	if (!intel_dmc_wl_check_range(reg.reg))
>  		return;
> 
> @@ -203,6 +212,9 @@ void intel_dmc_wl_put(struct drm_i915_private *i915,
> i915_reg_t reg)
>  	struct intel_dmc_wl *wl = &i915->display.wl;
>  	unsigned long flags;
> 
> +	if (DISPLAY_VER(i915) < 20)
> +		return;
> +
>  	if (!intel_dmc_wl_check_range(reg.reg))
>  		return;
> 
> --
> 2.39.2