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Hi, Shawn:
On Thu, 2024-07-04 at 01:35 +0000, Shawn Sung (宋孝謙) wrote:
> Hi CK,
>
> On Mon, 2024-07-01 at 03:10 +0000, CK Hu (胡俊光) wrote:
> > Hi, Shawn:
> >
> > On Thu, 2024-06-20 at 01:27 +0800, Hsiao Chien Sung via B4 Relay
> > wrote:
> > >
> > > External email : Please do not click links or open attachments
> > > until you have verified the sender or the content.
> > > From: Hsiao Chien Sung <shawn.sung@mediatek.com>
> > >
> > > Support "None" alpha blending mode on MediaTek's chips.
> > >
> > > Signed-off-by: Hsiao Chien Sung <shawn.sung@mediatek.com>
> > > ---
> > > drivers/gpu/drm/mediatek/mtk_ethdr.c | 13 ++++++++++---
> > > 1 file changed, 10 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/mediatek/mtk_ethdr.c
> > > b/drivers/gpu/drm/mediatek/mtk_ethdr.c
> > > index 36021cb8df62..48b714994492 100644
> > > --- a/drivers/gpu/drm/mediatek/mtk_ethdr.c
> > > +++ b/drivers/gpu/drm/mediatek/mtk_ethdr.c
> > > @@ -3,6 +3,7 @@
> > > * Copyright (c) 2021 MediaTek Inc.
> > > */
> > >
> > > +#include <drm/drm_blend.h>
> > > #include <drm/drm_fourcc.h>
> > > #include <drm/drm_framebuffer.h>
> > > #include <linux/clk.h>
> > > @@ -35,6 +36,7 @@
> > > #define MIX_SRC_L0_ENBIT(0)
> > > #define MIX_L_SRC_CON(n)(0x28 + 0x18 * (n))
> > > #define NON_PREMULTI_SOURCE(2 << 12)
> > > +#define PREMULTI_SOURCE(3 << 12)
> > > #define MIX_L_SRC_SIZE(n)(0x30 + 0x18 * (n))
> > > #define MIX_L_SRC_OFFSET(n)(0x34 + 0x18 * (n))
> > > #define MIX_FUNC_DCM00x120
> > > @@ -175,7 +177,13 @@ void mtk_ethdr_layer_config(struct device
> > > *dev, unsigned int idx,
> > > alpha_con |= state->base.alpha & MIXER_ALPHA;
> > > }
> > >
> > > -if (state->base.fb && !state->base.fb->format->has_alpha) {
> > > +if (state->base.pixel_blend_mode == DRM_MODE_BLEND_PIXEL_NONE)
> > > +alpha_con |= PREMULTI_SOURCE;
> >
> > To support DRM_MODE_BLEND_PIXEL_NONE, I think ignore pixel alpha is
> > enough. Why need this setting?
>
> Yes, by setting PREMULTI_SOURCE bit, ETHDR will ignore the pixel alpha
> of the layer.
In the later code, replace_src_a would be set to true.
I think replace_src_a is enough to implement DRM_MODE_BLEND_PIXEL_NONE.
So it's not necessary to set PREMULTI_SOURCE.
Regards,
CK
>
> Thanks,
> Shawn
>
> >
> > Regards,
> > CK
> >
> > > +else
> > > +alpha_con |= NON_PREMULTI_SOURCE;
> > > +
> > > +if ((state->base.fb && !state->base.fb->format->has_alpha) ||
> > > + state->base.pixel_blend_mode == DRM_MODE_BLEND_PIXEL_NONE) {
> > > /*
> > > * Mixer doesn't support CONST_BLD mode,
> > > * use a trick to make the output equivalent
> > > @@ -191,8 +199,7 @@ void mtk_ethdr_layer_config(struct device *dev,
> > > unsigned int idx,
> > > mtk_ddp_write(cmdq_pkt, pending->height << 16 | align_width,
> > > &mixer->cmdq_base,
> > > mixer->regs, MIX_L_SRC_SIZE(idx));
> > > mtk_ddp_write(cmdq_pkt, offset, &mixer->cmdq_base, mixer->regs,
> > > MIX_L_SRC_OFFSET(idx));
> > > -mtk_ddp_write_mask(cmdq_pkt, alpha_con, &mixer->cmdq_base, mixer-
> > > > regs, MIX_L_SRC_CON(idx),
> > >
> > > - 0x1ff);
> > > +mtk_ddp_write(cmdq_pkt, alpha_con, &mixer->cmdq_base, mixer->regs,
> > > MIX_L_SRC_CON(idx));
> > > mtk_ddp_write_mask(cmdq_pkt, BIT(idx), &mixer->cmdq_base, mixer-
> > > > regs, MIX_SRC_CON,
> > >
> > > BIT(idx));
> > > }
> > >
> > > --
> > > Git-146)
> > >
> > >
> > >
</pre>
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