Re: [PATCH 5/5] drm/i915: Use hweight8() for 8bit masks

[Jani Nikula <jani.nikula@linux.intel.com>]

On Wed, 21 Aug 2019, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Use hweight8() instead of hweight32() for 8bit masks. Doesn't actually
> matter for us since the arch code will go for hweight32() anyway, but
> maybe we stil want to do this for documentation purposes?

hweight32 is preparing for the distant future? ;)

I don't mind either way on this one, up to you.

The series is

Reviewed-by: Jani Nikula <jani.nikula@intel.com>


>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_pm.c | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index e86503023daf..b6089545c8fa 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -1327,8 +1327,8 @@ static int g4x_compute_pipe_wm(struct intel_crtc_state *crtc_state)
>  	struct intel_atomic_state *state =
>  		to_intel_atomic_state(crtc_state->base.state);
>  	struct g4x_wm_state *wm_state = &crtc_state->wm.g4x.optimal;
> -	int num_active_planes = hweight32(crtc_state->active_planes &
> -					  ~BIT(PLANE_CURSOR));
> +	int num_active_planes = hweight8(crtc_state->active_planes &
> +					 ~BIT(PLANE_CURSOR));
>  	const struct g4x_pipe_wm *raw;
>  	const struct intel_plane_state *old_plane_state;
>  	const struct intel_plane_state *new_plane_state;
> @@ -1659,7 +1659,7 @@ static int vlv_compute_fifo(struct intel_crtc_state *crtc_state)
>  		&crtc_state->wm.vlv.raw[VLV_WM_LEVEL_PM2];
>  	struct vlv_fifo_state *fifo_state = &crtc_state->wm.vlv.fifo_state;
>  	unsigned int active_planes = crtc_state->active_planes & ~BIT(PLANE_CURSOR);
> -	int num_active_planes = hweight32(active_planes);
> +	int num_active_planes = hweight8(active_planes);
>  	const int fifo_size = 511;
>  	int fifo_extra, fifo_left = fifo_size;
>  	int sprite0_fifo_extra = 0;
> @@ -1848,8 +1848,8 @@ static int vlv_compute_pipe_wm(struct intel_crtc_state *crtc_state)
>  	struct vlv_wm_state *wm_state = &crtc_state->wm.vlv.optimal;
>  	const struct vlv_fifo_state *fifo_state =
>  		&crtc_state->wm.vlv.fifo_state;
> -	int num_active_planes = hweight32(crtc_state->active_planes &
> -					  ~BIT(PLANE_CURSOR));
> +	int num_active_planes = hweight8(crtc_state->active_planes &
> +					 ~BIT(PLANE_CURSOR));
>  	bool needs_modeset = drm_atomic_crtc_needs_modeset(&crtc_state->base);
>  	const struct intel_plane_state *old_plane_state;
>  	const struct intel_plane_state *new_plane_state;
> @@ -3761,14 +3761,14 @@ bool intel_can_enable_sagv(struct intel_atomic_state *state)
>  	/*
>  	 * If there are no active CRTCs, no additional checks need be performed
>  	 */
> -	if (hweight32(state->active_pipes) == 0)
> +	if (hweight8(state->active_pipes) == 0)
>  		return true;
>  
>  	/*
>  	 * SKL+ workaround: bspec recommends we disable SAGV when we have
>  	 * more then one pipe enabled
>  	 */
> -	if (hweight32(state->active_pipes) > 1)
> +	if (hweight8(state->active_pipes) > 1)
>  		return false;
>  
>  	/* Since we're now guaranteed to only have one active CRTC... */
> @@ -3867,14 +3867,14 @@ skl_ddb_get_pipe_allocation_limits(struct drm_i915_private *dev_priv,
>  	if (WARN_ON(!state) || !crtc_state->base.active) {
>  		alloc->start = 0;
>  		alloc->end = 0;
> -		*num_active = hweight32(dev_priv->active_pipes);
> +		*num_active = hweight8(dev_priv->active_pipes);
>  		return;
>  	}
>  
>  	if (intel_state->active_pipe_changes)
> -		*num_active = hweight32(intel_state->active_pipes);
> +		*num_active = hweight8(intel_state->active_pipes);
>  	else
> -		*num_active = hweight32(dev_priv->active_pipes);
> +		*num_active = hweight8(dev_priv->active_pipes);
>  
>  	ddb_size = intel_get_ddb_size(dev_priv, crtc_state, total_data_rate,
>  				      *num_active, ddb);

-- 
Jani Nikula, Intel Open Source Graphics Center
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