<html><body><p> <pre> Hi, Shawn: On Thu, 2024-06-06 at 17:26 +0800, Shawn Sung wrote: > From: Hsiao Chien Sung <shawn.sung@mediatek.com> > > Support "Pre-multiplied" alpha blending mode on in OVL. > Before this patch, only the "coverage" mode is supported. > > Signed-off-by: Hsiao Chien Sung <shawn.sung@mediatek.com> > --- > drivers/gpu/drm/mediatek/mtk_disp_ovl.c | 40 +++++++++++++++++++++---- > 1 file changed, 34 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c > index 54a6f11aa867..de1633988921 100644 > --- a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c > +++ b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c > @@ -52,13 +52,16 @@ > #define GMC_THRESHOLD_HIGH((1 << GMC_THRESHOLD_BITS) / 4) > #define GMC_THRESHOLD_LOW((1 << GMC_THRESHOLD_BITS) / 8) > > +#define OVL_CON_CLRFMT_MANBIT(23) > #define OVL_CON_BYTE_SWAPBIT(24) > -#define OVL_CON_MTX_YUV_TO_RGB(6 << 16) > +#define OVL_CON_RGB_SWAPBIT(25) > #define OVL_CON_CLRFMT_RGB(1 << 12) > #define OVL_CON_CLRFMT_RGBA8888(2 << 12) > #define OVL_CON_CLRFMT_ARGB8888(3 << 12) > #define OVL_CON_CLRFMT_UYVY(4 << 12) > #define OVL_CON_CLRFMT_YUYV(5 << 12) > +#define OVL_CON_MTX_YUV_TO_RGB(6 << 16) > +#define OVL_CON_CLRFMT_PARGB8888(OVL_CON_CLRFMT_ARGB8888 | OVL_CON_CLRFMT_MAN) > #define OVL_CON_CLRFMT_RGB565(ovl)((ovl)->data->fmt_rgb565_is_0 ? \ > 0 : OVL_CON_CLRFMT_RGB) > #define OVL_CON_CLRFMT_RGB888(ovl)((ovl)->data->fmt_rgb565_is_0 ? \ > @@ -72,6 +75,8 @@ > #defineOVL_CON_VIRT_FLIPBIT(9) > #defineOVL_CON_HORZ_FLIPBIT(10) > > +#define OVL_COLOR_ALPHAGENMASK(31, 24) > + > static inline bool is_10bit_rgb(u32 fmt) > { > switch (fmt) { > @@ -296,7 +301,13 @@ void mtk_ovl_config(struct device *dev, unsigned int w, > if (w != 0 && h != 0) > mtk_ddp_write_relaxed(cmdq_pkt, h << 16 | w, &ovl->cmdq_reg, ovl->regs, > DISP_REG_OVL_ROI_SIZE); > -mtk_ddp_write_relaxed(cmdq_pkt, 0x0, &ovl->cmdq_reg, ovl->regs, DISP_REG_OVL_ROI_BGCLR); > + > +/* > + * The background color must be opaque black (ARGB), > + * otherwise the alpha blending will have no effect > + */ > +mtk_ddp_write_relaxed(cmdq_pkt, OVL_COLOR_ALPHA, &ovl->cmdq_reg, > + ovl->regs, DISP_REG_OVL_ROI_BGCLR); The coverage mode formula is: dst.RGB = src.RGB * src.A + dst.RGB * (1 - src.A) The pre-multiplied mode formula is: dst.RGB = src.RGB + dst.RGB * (1 - src.A) Both formula has no destination alpha (I think background color is last destination), why coverage mode work fine but pre-multiplied mode has something wrong? > > mtk_ddp_write(cmdq_pkt, 0x1, &ovl->cmdq_reg, ovl->regs, DISP_REG_OVL_RST); > mtk_ddp_write(cmdq_pkt, 0x0, &ovl->cmdq_reg, ovl->regs, DISP_REG_OVL_RST); > @@ -372,7 +383,8 @@ void mtk_ovl_layer_off(struct device *dev, unsigned int idx, > DISP_REG_OVL_RDMA_CTRL(idx)); > } > > -static unsigned int ovl_fmt_convert(struct mtk_disp_ovl *ovl, unsigned int fmt) > +static unsigned int ovl_fmt_convert(struct mtk_disp_ovl *ovl, unsigned int fmt, > + unsigned int blend_mode) > { > /* The return value in switch "MEM_MODE_INPUT_FORMAT_XXX" > * is defined in mediatek HW data sheet. > @@ -391,21 +403,35 @@ static unsigned int ovl_fmt_convert(struct mtk_disp_ovl *ovl, unsigned int fmt) > return OVL_CON_CLRFMT_RGB888(ovl) | OVL_CON_BYTE_SWAP; > case DRM_FORMAT_RGBX8888: > case DRM_FORMAT_RGBA8888: > +return blend_mode == DRM_MODE_BLEND_COVERAGE ? > + OVL_CON_CLRFMT_ARGB8888 : > + OVL_CON_CLRFMT_PARGB8888; > case DRM_FORMAT_RGBX1010102: > case DRM_FORMAT_RGBA1010102: > return OVL_CON_CLRFMT_ARGB8888; > case DRM_FORMAT_BGRX8888: > case DRM_FORMAT_BGRA8888: > +return OVL_CON_BYTE_SWAP | > + (blend_mode == DRM_MODE_BLEND_COVERAGE ? > + OVL_CON_CLRFMT_ARGB8888 : > + OVL_CON_CLRFMT_PARGB8888); > case DRM_FORMAT_BGRX1010102: > case DRM_FORMAT_BGRA1010102: > return OVL_CON_CLRFMT_ARGB8888 | OVL_CON_BYTE_SWAP; > case DRM_FORMAT_XRGB8888: > case DRM_FORMAT_ARGB8888: > +return blend_mode == DRM_MODE_BLEND_COVERAGE ? > + OVL_CON_CLRFMT_RGBA8888 : > + OVL_CON_CLRFMT_PARGB8888; In pre-multiplied mode, DRM_FORMAT_RGBA8888 and DRM_FORMAT_ARGB8888 would return the same value OVL_CON_CLRFMT_PARGB8888, so how does hardware distinguish these two format? > case DRM_FORMAT_XRGB2101010: > case DRM_FORMAT_ARGB2101010: > return OVL_CON_CLRFMT_RGBA8888; > case DRM_FORMAT_XBGR8888: > case DRM_FORMAT_ABGR8888: > +return OVL_CON_RGB_SWAP | > + (blend_mode == DRM_MODE_BLEND_COVERAGE ? > + OVL_CON_CLRFMT_RGBA8888 : > + OVL_CON_CLRFMT_PARGB8888); Originally, DRM_MODE_BLEND_COVERAGE and DRM_FORMAT_ABGR8888 would return OVL_CON_CLRFMT_RGBA8888 | OVL_CON_BYTE_SWAP but this patch return OVL_CON_CLRFMT_RGBA8888 | OVL_CON_RGB_SWAP This is not related to pre-multiplied, so separate this to another patch. > case DRM_FORMAT_XBGR2101010: > case DRM_FORMAT_ABGR2101010: > return OVL_CON_CLRFMT_RGBA8888 | OVL_CON_BYTE_SWAP; > @@ -448,9 +474,11 @@ void mtk_ovl_layer_config(struct device *dev, unsigned int idx, > return; > } > > -con = ovl_fmt_convert(ovl, fmt); > -if (state->base.fb && state->base.fb->format->has_alpha) > -con |= OVL_CON_AEN | OVL_CON_ALPHA; > +con = ovl_fmt_convert(ovl, fmt, blend_mode); > +if (state->base.fb) { > +con |= OVL_CON_AEN; > +con |= state->base.alpha & OVL_CON_ALPHA; This modification is to support constant alpha, not related to pre-multiplied alpha. So separate this to another patch. Regards, CK > +} > > /* CONST_BLD must be enabled for XRGB formats although the alpha channel > * can be ignored, or OVL will still read the value from memory. </pre> </p></body></html><pre>************* MEDIATEK Confidentiality Notice ******************** The information contained in this e-mail message (including any attachments) may be confidential, proprietary, privileged, or otherwise exempt from disclosure under applicable laws. It is intended to be conveyed only to the designated recipient(s). Any use, dissemination, distribution, printing, retaining or copying of this e-mail (including its attachments) by unintended recipient(s) is strictly prohibited and may be unlawful. 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