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

[Christopher Obbard]

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 at RG24
>   modetest -s <connector_id>@<crtc_id>:1920x1080-60 at 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 at kwiboo.se>

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?


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);
>  
>  	/*