Op 23-08-18 om 00:57 schreef Matt Roper:
> On Wed, Aug 15, 2018 at 12:34:05PM +0200, Maarten Lankhorst wrote:
>> Add plane alpha blending support with the different blend modes.
>> This has been tested on a icl to show the correct results,
>> on earlier platforms small rounding errors cause issues. But this
>> already happens case with fully transparant or fully opaque RGB8888
>> fb's.
>>
>> The recommended HW workaround is to disable alpha blending when the
>> plane alpha is 0 (transparant, hide plane) or 0xff (opaque, disable 
>> blending).
>> This is easy to implement on any platform, so just do that.
>>
>> The tests for userspace are also available, and pass on gen11.
>>
>> Changes since v1:
>> - Change mistaken < 0xff0 to 0xff00.
>> - Only set PLANE_KEYMSK_ALPHA_ENABLE when plane alpha < 0xff00, ignore blend 
>> mode.
>> - Rework disabling FBC when per pixel alpha is used.
>>
>> Signed-off-by: Maarten Lankhorst <[email protected]>
> One question and one minor suggestion inline below, but otherwise,
>
> Reviewed-by: Matt Roper <[email protected]>
>
>> ---
>>  drivers/gpu/drm/i915/i915_drv.h      |  2 +
>>  drivers/gpu/drm/i915/i915_reg.h      |  2 +
>>  drivers/gpu/drm/i915/intel_display.c | 58 +++++++++++++++++++---------
>>  drivers/gpu/drm/i915/intel_fbc.c     |  8 ++++
>>  drivers/gpu/drm/i915/intel_sprite.c  | 23 ++++++++++-
>>  5 files changed, 73 insertions(+), 20 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_drv.h 
>> b/drivers/gpu/drm/i915/i915_drv.h
>> index 3fa56b960ef2..29f75da5fa8c 100644
>> --- a/drivers/gpu/drm/i915/i915_drv.h
>> +++ b/drivers/gpu/drm/i915/i915_drv.h
>> @@ -545,6 +545,8 @@ struct intel_fbc {
>>                      int adjusted_y;
>>  
>>                      int y;
>> +
>> +                    uint16_t pixel_blend_mode;
>>              } plane;
>>  
>>              struct {
>> diff --git a/drivers/gpu/drm/i915/i915_reg.h 
>> b/drivers/gpu/drm/i915/i915_reg.h
>> index 0c9f03dda569..93a1d87cdeb2 100644
>> --- a/drivers/gpu/drm/i915/i915_reg.h
>> +++ b/drivers/gpu/drm/i915/i915_reg.h
>> @@ -6561,8 +6561,10 @@ enum {
>>  #define _PLANE_KEYVAL_2_A                   0x70294
>>  #define _PLANE_KEYMSK_1_A                   0x70198
>>  #define _PLANE_KEYMSK_2_A                   0x70298
>> +#define  PLANE_KEYMSK_ALPHA_ENABLE          (1 << 31)
>>  #define _PLANE_KEYMAX_1_A                   0x701a0
>>  #define _PLANE_KEYMAX_2_A                   0x702a0
>> +#define  PLANE_KEYMAX_ALPHA_SHIFT           24
>>  #define _PLANE_AUX_DIST_1_A                 0x701c0
>>  #define _PLANE_AUX_DIST_2_A                 0x702c0
>>  #define _PLANE_AUX_OFFSET_1_A                       0x701c4
>> diff --git a/drivers/gpu/drm/i915/intel_display.c 
>> b/drivers/gpu/drm/i915/intel_display.c
>> index a0345e7d3c2b..aedad3674b0d 100644
>> --- a/drivers/gpu/drm/i915/intel_display.c
>> +++ b/drivers/gpu/drm/i915/intel_display.c
>> @@ -3167,6 +3167,12 @@ int skl_check_plane_surface(const struct 
>> intel_crtc_state *crtc_state,
>>              return -EINVAL;
>>      }
>>  
>> +    /* HW only has 8 bits pixel precision, disable plane if invisible */
>> +    if (!(plane_state->base.alpha >> 8)) {
>> +            plane_state->base.visible = false;
>> +            return 0;
>> +    }
>> +
>>      if (!plane_state->base.visible)
>>              return 0;
>>  
>> @@ -3512,30 +3518,39 @@ static u32 skl_plane_ctl_format(uint32_t 
>> pixel_format)
>>      return 0;
>>  }
>>  
>> -/*
>> - * XXX: For ARBG/ABGR formats we default to expecting scanout buffers
>> - * to be already pre-multiplied. We need to add a knob (or a different
>> - * DRM_FORMAT) for user-space to configure that.
>> - */
>> -static u32 skl_plane_ctl_alpha(uint32_t pixel_format)
>> +static u32 skl_plane_ctl_alpha(const struct intel_plane_state *plane_state)
>>  {
>> -    switch (pixel_format) {
>> -    case DRM_FORMAT_ABGR8888:
>> -    case DRM_FORMAT_ARGB8888:
>> +    if (!plane_state->base.fb->format->has_alpha)
>> +            return PLANE_CTL_ALPHA_DISABLE;
>> +
>> +    switch (plane_state->base.pixel_blend_mode) {
>> +    case DRM_MODE_BLEND_PIXEL_NONE:
>> +            return PLANE_CTL_ALPHA_DISABLE;
>> +    case DRM_MODE_BLEND_PREMULTI:
>>              return PLANE_CTL_ALPHA_SW_PREMULTIPLY;
>> +    case DRM_MODE_BLEND_COVERAGE:
>> +            return PLANE_CTL_ALPHA_HW_PREMULTIPLY;
>>      default:
>> -            return PLANE_CTL_ALPHA_DISABLE;
>> +            MISSING_CASE(plane_state->base.pixel_blend_mode);
>> +            return 0;
> Maybe just add the MISSING_CASE line before the current return?  The
> macro still expands to 0, so leaving that makes it slightly more clear
> what the default fallback is.  Same for the glk_ function below.
Makes sense, will change that in v3. :)
>>      }
>>  }
>>  
>> -static u32 glk_plane_color_ctl_alpha(uint32_t pixel_format)
>> +static u32 glk_plane_color_ctl_alpha(const struct intel_plane_state 
>> *plane_state)
>>  {
>> -    switch (pixel_format) {
>> -    case DRM_FORMAT_ABGR8888:
>> -    case DRM_FORMAT_ARGB8888:
>> +    if (!plane_state->base.fb->format->has_alpha)
>> +            return PLANE_COLOR_ALPHA_DISABLE;
>> +
>> +    switch (plane_state->base.pixel_blend_mode) {
>> +    case DRM_MODE_BLEND_PIXEL_NONE:
>> +            return PLANE_COLOR_ALPHA_DISABLE;
>> +    case DRM_MODE_BLEND_PREMULTI:
>>              return PLANE_COLOR_ALPHA_SW_PREMULTIPLY;
>> +    case DRM_MODE_BLEND_COVERAGE:
>> +            return PLANE_COLOR_ALPHA_HW_PREMULTIPLY;
>>      default:
>> -            return PLANE_COLOR_ALPHA_DISABLE;
>> +            MISSING_CASE(plane_state->base.pixel_blend_mode);
>> +            return 0;
>>      }
>>  }
>>  
>> @@ -3611,7 +3626,7 @@ u32 skl_plane_ctl(const struct intel_crtc_state 
>> *crtc_state,
>>      plane_ctl = PLANE_CTL_ENABLE;
>>  
>>      if (INTEL_GEN(dev_priv) < 10 && !IS_GEMINILAKE(dev_priv)) {
>> -            plane_ctl |= skl_plane_ctl_alpha(fb->format->format);
>> +            plane_ctl |= skl_plane_ctl_alpha(plane_state);
>>              plane_ctl |=
>>                      PLANE_CTL_PIPE_GAMMA_ENABLE |
>>                      PLANE_CTL_PIPE_CSC_ENABLE |
>> @@ -3653,7 +3668,7 @@ u32 glk_plane_color_ctl(const struct intel_crtc_state 
>> *crtc_state,
>>              plane_color_ctl |= PLANE_COLOR_PIPE_CSC_ENABLE;
>>      }
>>      plane_color_ctl |= PLANE_COLOR_PLANE_GAMMA_DISABLE;
>> -    plane_color_ctl |= glk_plane_color_ctl_alpha(fb->format->format);
>> +    plane_color_ctl |= glk_plane_color_ctl_alpha(plane_state);
>>  
>>      if (fb->format->is_yuv) {
>>              if (plane_state->base.color_encoding == DRM_COLOR_YCBCR_BT709)
>> @@ -13792,7 +13807,7 @@ intel_primary_plane_create(struct drm_i915_private 
>> *dev_priv, enum pipe pipe)
>>                                                 DRM_MODE_ROTATE_0,
>>                                                 supported_rotations);
>>  
>> -    if (INTEL_GEN(dev_priv) >= 9)
>> +    if (INTEL_GEN(dev_priv) >= 9) {
>>              drm_plane_create_color_properties(&primary->base,
>>                                                BIT(DRM_COLOR_YCBCR_BT601) |
>>                                                BIT(DRM_COLOR_YCBCR_BT709),
>> @@ -13801,6 +13816,13 @@ intel_primary_plane_create(struct drm_i915_private 
>> *dev_priv, enum pipe pipe)
>>                                                DRM_COLOR_YCBCR_BT709,
>>                                                
>> DRM_COLOR_YCBCR_LIMITED_RANGE);
>>  
>> +            drm_plane_create_alpha_property(&primary->base);
>> +            drm_plane_create_blend_mode_property(&primary->base,
>> +                                                 
>> BIT(DRM_MODE_BLEND_PIXEL_NONE) |
>> +                                                 
>> BIT(DRM_MODE_BLEND_PREMULTI) |
>> +                                                 
>> BIT(DRM_MODE_BLEND_COVERAGE));
>> +    }
>> +
>>      drm_plane_helper_add(&primary->base, &intel_plane_helper_funcs);
>>  
>>      return primary;
>> diff --git a/drivers/gpu/drm/i915/intel_fbc.c 
>> b/drivers/gpu/drm/i915/intel_fbc.c
>> index 75a6bbf3ada1..42a49fe34ba3 100644
>> --- a/drivers/gpu/drm/i915/intel_fbc.c
>> +++ b/drivers/gpu/drm/i915/intel_fbc.c
>> @@ -674,6 +674,8 @@ static void intel_fbc_update_state_cache(struct 
>> intel_crtc *crtc,
>>      cache->plane.adjusted_y = plane_state->main.y;
>>      cache->plane.y = plane_state->base.src.y1 >> 16;
>>  
>> +    cache->plane.pixel_blend_mode = plane_state->base.pixel_blend_mode;
>> +
>>      if (!cache->plane.visible)
>>              return;
>>  
>> @@ -748,6 +750,12 @@ static bool intel_fbc_can_activate(struct intel_crtc 
>> *crtc)
>>              return false;
>>      }
>>  
>> +    if (cache->plane.pixel_blend_mode != DRM_MODE_BLEND_PIXEL_NONE &&
>> +        cache->fb.format->has_alpha) {
>> +            fbc->no_fbc_reason = "per-pixel alpha blending is incompatible 
>> with FBC";
>> +            return false;
>> +    }
> This sounds reasonable, but is there somewhere in the b-spec that
> explains this explicitly?  The FBC_CTL description lists pixel format
> restrictions (16 or 32 bit 888 RGB), but nothing explicitly about
> blending or alpha.
PLANE_COLOR_CTL alpha mode, and PLANE_CTL's alpha mode both mention
in bspec that per pixel alpha is not compatible with FBC. :)

~Maarten
>
> Matt
>
>> +
>>      /* WaFbcExceedCdClockThreshold:hsw,bdw */
>>      if ((IS_HASWELL(dev_priv) || IS_BROADWELL(dev_priv)) &&
>>          cache->crtc.hsw_bdw_pixel_rate >= dev_priv->cdclk.hw.cdclk * 95 / 
>> 100) {
>> diff --git a/drivers/gpu/drm/i915/intel_sprite.c 
>> b/drivers/gpu/drm/i915/intel_sprite.c
>> index f7026e887fa9..4639ef9bde94 100644
>> --- a/drivers/gpu/drm/i915/intel_sprite.c
>> +++ b/drivers/gpu/drm/i915/intel_sprite.c
>> @@ -252,6 +252,7 @@ skl_update_plane(struct intel_plane *plane,
>>      uint32_t src_w = drm_rect_width(&plane_state->base.src) >> 16;
>>      uint32_t src_h = drm_rect_height(&plane_state->base.src) >> 16;
>>      unsigned long irqflags;
>> +    u32 keymsk = 0, keymax = 0;
>>  
>>      /* Sizes are 0 based */
>>      src_w--;
>> @@ -267,10 +268,19 @@ skl_update_plane(struct intel_plane *plane,
>>  
>>      if (key->flags) {
>>              I915_WRITE_FW(PLANE_KEYVAL(pipe, plane_id), key->min_value);
>> -            I915_WRITE_FW(PLANE_KEYMAX(pipe, plane_id), key->max_value);
>> -            I915_WRITE_FW(PLANE_KEYMSK(pipe, plane_id), key->channel_mask);
>> +
>> +            keymax |= key->max_value & 0xffffff;
>> +            keymsk |= key->channel_mask & 0x3ffffff;
>>      }
>>  
>> +    keymax |= (plane_state->base.alpha >> 8) << PLANE_KEYMAX_ALPHA_SHIFT;
>> +
>> +    if (plane_state->base.alpha < 0xff00)
>> +            keymsk |= PLANE_KEYMSK_ALPHA_ENABLE;
>> +
>> +    I915_WRITE_FW(PLANE_KEYMAX(pipe, plane_id), keymax);
>> +    I915_WRITE_FW(PLANE_KEYMSK(pipe, plane_id), keymsk);
>> +
>>      I915_WRITE_FW(PLANE_OFFSET(pipe, plane_id), (y << 16) | x);
>>      I915_WRITE_FW(PLANE_STRIDE(pipe, plane_id), stride);
>>      I915_WRITE_FW(PLANE_SIZE(pipe, plane_id), (src_h << 16) | src_w);
>> @@ -1650,6 +1660,15 @@ intel_sprite_plane_create(struct drm_i915_private 
>> *dev_priv,
>>                                        DRM_COLOR_YCBCR_BT709,
>>                                        DRM_COLOR_YCBCR_LIMITED_RANGE);
>>  
>> +    if (INTEL_GEN(dev_priv) >= 9) {
>> +            drm_plane_create_alpha_property(&intel_plane->base);
>> +
>> +            drm_plane_create_blend_mode_property(&intel_plane->base,
>> +                                                 
>> BIT(DRM_MODE_BLEND_PIXEL_NONE) |
>> +                                                 
>> BIT(DRM_MODE_BLEND_PREMULTI) |
>> +                                                 
>> BIT(DRM_MODE_BLEND_COVERAGE));
>> +    }
>> +
>>      drm_plane_helper_add(&intel_plane->base, &intel_plane_helper_funcs);
>>  
>>      return intel_plane;
>> -- 
>> 2.18.0
>>
>> _______________________________________________
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>> https://lists.freedesktop.org/mailman/listinfo/dri-devel


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