Re: [PATCH 5/9] drm/i915/gen9: minimum scanlines for Y tile is not always 4

[Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx>]

Hi,

On 22/09/2016 22:00, Paulo Zanoni wrote:
> During watermarks calculations, this value is used in 3 different
> places. Only one of them was not using a hardcoded 4. Move the code up
> so everybody can benefit from the actual value.
>
> This should only help on situations with Y tiling + 90/270 rotation +
> 1 or 2 bpp or NV12.

I don't think bothering stable with this was required since 90/270 on 
NV12 was never fully enabled AFAIR. Unless Ville accidentaly enabled it 
in his recent rewrite? But it was not put in due instability issues so I 
hope not.

Regards,

Tvrtko

> Cc: stable@xxxxxxxxxxxxxxx
> Reviewed-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx>
> ---
>   drivers/gpu/drm/i915/intel_pm.c | 56 +++++++++++++++++++++++------------------
>   1 file changed, 32 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index ee561c2..a7f5f7f 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -3495,7 +3495,8 @@ static uint32_t skl_wm_method1(uint32_t pixel_rate, uint8_t cpp, uint32_t latenc
>   
>   static uint32_t skl_wm_method2(uint32_t pixel_rate, uint32_t pipe_htotal,
>   			       uint32_t horiz_pixels, uint8_t cpp,
> -			       uint64_t tiling, uint32_t latency)
> +			       uint64_t tiling, uint32_t latency,
> +			       uint32_t y_min_scanlines)
>   {
>   	uint32_t ret;
>   	uint32_t plane_bytes_per_line, plane_blocks_per_line;
> @@ -3508,9 +3509,9 @@ static uint32_t skl_wm_method2(uint32_t pixel_rate, uint32_t pipe_htotal,
>   
>   	if (tiling == I915_FORMAT_MOD_Y_TILED ||
>   	    tiling == I915_FORMAT_MOD_Yf_TILED) {
> -		plane_bytes_per_line *= 4;
> +		plane_bytes_per_line *= y_min_scanlines;
>   		plane_blocks_per_line = DIV_ROUND_UP(plane_bytes_per_line, 512);
> -		plane_blocks_per_line /= 4;
> +		plane_blocks_per_line /= y_min_scanlines;
>   	} else if (tiling == DRM_FORMAT_MOD_NONE) {
>   		plane_blocks_per_line = DIV_ROUND_UP(plane_bytes_per_line, 512) + 1;
>   	} else {
> @@ -3567,6 +3568,7 @@ static int skl_compute_plane_wm(const struct drm_i915_private *dev_priv,
>   	uint8_t cpp;
>   	uint32_t width = 0, height = 0;
>   	uint32_t plane_pixel_rate;
> +	uint32_t y_min_scanlines;
>   
>   	if (latency == 0 || !cstate->base.active || !intel_pstate->base.visible) {
>   		*enabled = false;
> @@ -3582,38 +3584,44 @@ static int skl_compute_plane_wm(const struct drm_i915_private *dev_priv,
>   	cpp = drm_format_plane_cpp(fb->pixel_format, 0);
>   	plane_pixel_rate = skl_adjusted_plane_pixel_rate(cstate, intel_pstate);
>   
> +	if (intel_rotation_90_or_270(pstate->rotation)) {
> +		int cpp = (fb->pixel_format == DRM_FORMAT_NV12) ?
> +			drm_format_plane_cpp(fb->pixel_format, 1) :
> +			drm_format_plane_cpp(fb->pixel_format, 0);
> +
> +		switch (cpp) {
> +		case 1:
> +			y_min_scanlines = 16;
> +			break;
> +		case 2:
> +			y_min_scanlines = 8;
> +			break;
> +		default:
> +			WARN(1, "Unsupported pixel depth for rotation");
> +		case 4:
> +			y_min_scanlines = 4;
> +			break;
> +		}
> +	} else {
> +		y_min_scanlines = 4;
> +	}
> +
>   	method1 = skl_wm_method1(plane_pixel_rate, cpp, latency);
>   	method2 = skl_wm_method2(plane_pixel_rate,
>   				 cstate->base.adjusted_mode.crtc_htotal,
>   				 width,
>   				 cpp,
>   				 fb->modifier[0],
> -				 latency);
> +				 latency,
> +				 y_min_scanlines);
>   
>   	plane_bytes_per_line = width * cpp;
>   	plane_blocks_per_line = DIV_ROUND_UP(plane_bytes_per_line, 512);
>   
>   	if (fb->modifier[0] == I915_FORMAT_MOD_Y_TILED ||
>   	    fb->modifier[0] == I915_FORMAT_MOD_Yf_TILED) {
> -		uint32_t min_scanlines = 4;
> -		uint32_t y_tile_minimum;
> -		if (intel_rotation_90_or_270(pstate->rotation)) {
> -			int cpp = (fb->pixel_format == DRM_FORMAT_NV12) ?
> -				drm_format_plane_cpp(fb->pixel_format, 1) :
> -				drm_format_plane_cpp(fb->pixel_format, 0);
> -
> -			switch (cpp) {
> -			case 1:
> -				min_scanlines = 16;
> -				break;
> -			case 2:
> -				min_scanlines = 8;
> -				break;
> -			case 8:
> -				WARN(1, "Unsupported pixel depth for rotation");
> -			}
> -		}
> -		y_tile_minimum = plane_blocks_per_line * min_scanlines;
> +		uint32_t y_tile_minimum = plane_blocks_per_line *
> +					  y_min_scanlines;
>   		selected_result = max(method2, y_tile_minimum);
>   	} else {
>   		if ((ddb_allocation / plane_blocks_per_line) >= 1)
> @@ -3628,7 +3636,7 @@ static int skl_compute_plane_wm(const struct drm_i915_private *dev_priv,
>   	if (level >= 1 && level <= 7) {
>   		if (fb->modifier[0] == I915_FORMAT_MOD_Y_TILED ||
>   		    fb->modifier[0] == I915_FORMAT_MOD_Yf_TILED)
> -			res_lines += 4;
> +			res_lines += y_min_scanlines;
>   		else
>   			res_blocks++;
>   	}

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