diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c b/drivers/gpu/drm/sun4i/sun4i_backend.c index e2f0d8fc3ddebc7ef73e77654da37e9df3ea4b14..f6d8d0d4d5bfee4fedea30d7c4c1c9d9b7703846 100644 --- a/drivers/gpu/drm/sun4i/sun4i_backend.c +++ b/drivers/gpu/drm/sun4i/sun4i_backend.c @@ -34,6 +34,9 @@ struct sun4i_backend_quirks { /* backend <-> TCON muxing selection done in backend */ bool needs_output_muxing; + + /* alpha at the lowest z position is not always supported */ + bool supports_lowest_plane_alpha; }; static const u32 sunxi_rgb2yuv_coef[12] = { @@ -457,12 +460,14 @@ static int sun4i_backend_atomic_check(struct sunxi_engine *engine, struct drm_crtc_state *crtc_state) { struct drm_plane_state *plane_states[SUN4I_BACKEND_NUM_LAYERS] = { 0 }; + struct sun4i_backend *backend = engine_to_sun4i_backend(engine); struct drm_atomic_state *state = crtc_state->state; struct drm_device *drm = state->dev; struct drm_plane *plane; unsigned int num_planes = 0; unsigned int num_alpha_planes = 0; unsigned int num_frontend_planes = 0; + unsigned int num_alpha_planes_max = 1; unsigned int num_yuv_planes = 0; unsigned int current_pipe = 0; unsigned int i; @@ -526,33 +531,40 @@ static int sun4i_backend_atomic_check(struct sunxi_engine *engine, * the layer with the highest priority. * * The second step is the actual alpha blending, that takes - * the two pipes as input, and uses the eventual alpha + * the two pipes as input, and uses the potential alpha * component to do the transparency between the two. * - * This two steps scenario makes us unable to guarantee a + * This two-step scenario makes us unable to guarantee a * robust alpha blending between the 4 layers in all * situations, since this means that we need to have one layer * with alpha at the lowest position of our two pipes. * - * However, we cannot even do that, since the hardware has a - * bug where the lowest plane of the lowest pipe (pipe 0, - * priority 0), if it has any alpha, will discard the pixel - * entirely and just display the pixels in the background - * color (black by default). + * However, we cannot even do that on every platform, since + * the hardware has a bug where the lowest plane of the lowest + * pipe (pipe 0, priority 0), if it has any alpha, will + * discard the pixel data entirely and just display the pixels + * in the background color (black by default). * - * This means that we effectively have only three valid - * configurations with alpha, all of them with the alpha being - * on pipe1 with the lowest position, which can be 1, 2 or 3 - * depending on the number of planes and their zpos. + * This means that on the affected platforms, we effectively + * have only three valid configurations with alpha, all of + * them with the alpha being on pipe1 with the lowest + * position, which can be 1, 2 or 3 depending on the number of + * planes and their zpos. */ - if (num_alpha_planes > SUN4I_BACKEND_NUM_ALPHA_LAYERS) { + + /* For platforms that are not affected by the issue described above. */ + if (backend->quirks->supports_lowest_plane_alpha) + num_alpha_planes_max++; + + if (num_alpha_planes > num_alpha_planes_max) { DRM_DEBUG_DRIVER("Too many planes with alpha, rejecting...\n"); return -EINVAL; } /* We can't have an alpha plane at the lowest position */ - if (plane_states[0]->fb->format->has_alpha || - (plane_states[0]->alpha != DRM_BLEND_ALPHA_OPAQUE)) + if (!backend->quirks->supports_lowest_plane_alpha && + (plane_states[0]->fb->format->has_alpha || + (plane_states[0]->alpha != DRM_BLEND_ALPHA_OPAQUE))) return -EINVAL; for (i = 1; i < num_planes; i++) { @@ -937,9 +949,11 @@ static const struct sun4i_backend_quirks sun6i_backend_quirks = { static const struct sun4i_backend_quirks sun7i_backend_quirks = { .needs_output_muxing = true, + .supports_lowest_plane_alpha = true, }; static const struct sun4i_backend_quirks sun8i_a33_backend_quirks = { + .supports_lowest_plane_alpha = true, }; static const struct sun4i_backend_quirks sun9i_backend_quirks = { diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.h b/drivers/gpu/drm/sun4i/sun4i_backend.h index ad6609323f0eb70c8e581d39599a9d864ea3ad62..e3d4c6035eb2511b32fd8a93f90cc1498a11cb5e 100644 --- a/drivers/gpu/drm/sun4i/sun4i_backend.h +++ b/drivers/gpu/drm/sun4i/sun4i_backend.h @@ -167,7 +167,6 @@ #define SUN4I_BACKEND_PIPE_OFF(p) (0x5000 + (0x400 * (p))) #define SUN4I_BACKEND_NUM_LAYERS 4 -#define SUN4I_BACKEND_NUM_ALPHA_LAYERS 1 #define SUN4I_BACKEND_NUM_FRONTEND_LAYERS 1 #define SUN4I_BACKEND_NUM_YUV_PLANES 1