Re: [PATCH] drm/rockchip: vop: Fix color for RGB888/BGR888 format on VOP full

[Andy Yan]

Hi:

On 10/24/23 16:49, Christopher Obbard wrote:
> Hi Jonas,
>
> On Mon, 2023-10-23 at 21:11 +0000, Jonas Karlman wrote:
> > Use of DRM_FORMAT_RGB888 and DRM_FORMAT_BGR888 on e.g. RK3288, RK3328
> > and RK3399 result in wrong colors being displayed.
> >
> > The issue can be observed using modetest:
> >
> >    modetest -s <connector_id>@<crtc_id>:1920x1080-60@RG24
> >    modetest -s <connector_id>@<crtc_id>:1920x1080-60@BG24
> >
> > Vendor 4.4 kernel apply an inverted rb swap for these formats on VOP
> > full (major = 3).
> >
> > Fix colors by applying rb swap similar to vendor 4.4 kernel.
> >
> > Signed-off-by: Jonas Karlman <jonas@xxxxxxxxx>
> How about a fixes tag? Seems like this was introduced in commit 85a359f25388
> ("drm/rockchip: Add BGR formats to VOP")
>
> > ---
> >   drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 9 ++++++---
> >   1 file changed, 6 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
> > b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
> > index b3d0b6ae9294..a1ce09a22f83 100644
> > --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
> > +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
> > @@ -247,14 +247,17 @@ static inline void vop_cfg_done(struct vop *vop)
> >   	VOP_REG_SET(vop, common, cfg_done, 1);
> >   }
> >   
> > -static bool has_rb_swapped(uint32_t format)
> > +static bool has_rb_swapped(uint32_t version, uint32_t format)
> >   {
> >   	switch (format) {
> >   	case DRM_FORMAT_XBGR8888:
> >   	case DRM_FORMAT_ABGR8888:
> > -	case DRM_FORMAT_BGR888:
> >   	case DRM_FORMAT_BGR565:
> >   		return true;
> > +	case DRM_FORMAT_RGB888:
> > +		return VOP_MAJOR(version) == 3;
> > +	case DRM_FORMAT_BGR888:
> > +		return VOP_MAJOR(version) != 3;
> The hardcoded bits are quite scary as it applies to all hardware variants ;-).
> Is it worth adding an inline comment to describe what is going on and how it
> relates to VOPL and VOPH? Or would it be even better to add this as a quirk in
> the various vop_data structs?


Every vop hardware has a version(including VOPB/VOPL), so I think use 
VOP_MAJOR to distinguish is ok. Of course it's better

to add some comments. As for adding some quirk in vop_data, I have the 
idea of adding a table to describe the drm format and it's (rb/uv swap, 
afbc)

capability, but I think this is can be done in the future.

> Cheers!
>
> Chris
>
> >   	default:
> >   		return false;
> >   	}
> > @@ -1035,7 +1038,7 @@ static void vop_plane_atomic_update(struct drm_plane
> > *plane,
> >   	VOP_WIN_SET(vop, win, dsp_info, dsp_info);
> >   	VOP_WIN_SET(vop, win, dsp_st, dsp_st);
> >   
> > -	rb_swap = has_rb_swapped(fb->format->format);
> > +	rb_swap = has_rb_swapped(vop->data->version, fb->format->format);
> >   	VOP_WIN_SET(vop, win, rb_swap, rb_swap);
> >   
> >   	/*
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