linux-kernel - Re: [PATCH v5 2/9] drm/mediatek: dsi: Fix DSI RGB666 formats and definitions

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Date: Thu, 15 Feb 2024 06:12:18 +0000
From: CK Hu (胡俊光) <ck.hu@...iatek.com>
To: "angelogioacchino.delregno@...labora.com"
	<angelogioacchino.delregno@...labora.com>, "chunkuang.hu@...nel.org"
	<chunkuang.hu@...nel.org>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-mediatek@...ts.infradead.org" <linux-mediatek@...ts.infradead.org>,
	"kernel@...labora.com" <kernel@...labora.com>, "daniel@...ll.ch"
	<daniel@...ll.ch>, "p.zabel@...gutronix.de" <p.zabel@...gutronix.de>,
	"dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
	"amergnat@...libre.com" <amergnat@...libre.com>, "airlied@...il.com"
	<airlied@...il.com>, "linux-arm-kernel@...ts.infradead.org"
	<linux-arm-kernel@...ts.infradead.org>, "matthias.bgg@...il.com"
	<matthias.bgg@...il.com>
Subject: Re: [PATCH v5 2/9] drm/mediatek: dsi: Fix DSI RGB666 formats and
 definitions

Hi, Angelo:

On Wed, 2024-02-07 at 15:53 +0100, AngeloGioacchino Del Regno wrote:
> The register bits definitions for RGB666 formats are wrong in
> multiple
> ways: first, in the DSI_PS_SEL bits region, the Packed 18-bits RGB666
> format is selected with bit 1, while the Loosely Packed one is bit 2,
> and second - the definition name "LOOSELY_PS_18BIT_RGB666" is wrong
> because the loosely packed format is 24 bits instead!
> 
> Either way, functions mtk_dsi_ps_control_vact() and
> mtk_dsi_ps_control()
> do not even agree on the DSI_PS_SEL bit to set in DSI_PSCTRL: one
> sets
> loosely packed (24) on RGB666, the other sets packed (18), and the
> other
> way around for RGB666_PACKED.
> 
> Fixing this entire stack of issues is done in one go:
>  - Use the correct bit for the Loosely Packed RGB666 definition
>  - Rename LOOSELY_PS_18BIT_RGB666 to LOOSELY_PS_24BIT_RGB666
>  - Change ps_bpp_mode in mtk_dsi_ps_control_vact() to set:
>     - Loosely Packed, 24-bits for MIPI_DSI_FMT_RGB666
>     - Packed, 18-bits for MIPI_DSI_FMT_RGB666_PACKED

Reviewed-by: CK Hu <ck.hu@...iatek.com>

> 
> Fixes: 2e54c14e310f ("drm/mediatek: Add DSI sub driver")
> Reviewed-by: Alexandre Mergnat <amergnat@...libre.com>
> Signed-off-by: AngeloGioacchino Del Regno <
> angelogioacchino.delregno@...labora.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index c66e18006070..8af0afbe9e3d 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -71,8 +71,8 @@
>  #define DSI_PS_WC			GENMASK(13, 0)
>  #define DSI_PS_SEL			GENMASK(17, 16)
>  #define PACKED_PS_16BIT_RGB565		(0 << 16)
> -#define LOOSELY_PS_18BIT_RGB666		(1 << 16)
> -#define PACKED_PS_18BIT_RGB666		(2 << 16)
> +#define PACKED_PS_18BIT_RGB666		(1 << 16)
> +#define LOOSELY_PS_24BIT_RGB666		(2 << 16)
>  #define PACKED_PS_24BIT_RGB888		(3 << 16)
>  
>  #define DSI_VSA_NL		0x20
> @@ -370,10 +370,10 @@ static void mtk_dsi_ps_control_vact(struct
> mtk_dsi *dsi)
>  		ps_bpp_mode |= PACKED_PS_24BIT_RGB888;
>  		break;
>  	case MIPI_DSI_FMT_RGB666:
> -		ps_bpp_mode |= PACKED_PS_18BIT_RGB666;
> +		ps_bpp_mode |= LOOSELY_PS_24BIT_RGB666;
>  		break;
>  	case MIPI_DSI_FMT_RGB666_PACKED:
> -		ps_bpp_mode |= LOOSELY_PS_18BIT_RGB666;
> +		ps_bpp_mode |= PACKED_PS_18BIT_RGB666;
>  		break;
>  	case MIPI_DSI_FMT_RGB565:
>  		ps_bpp_mode |= PACKED_PS_16BIT_RGB565;
> @@ -427,7 +427,7 @@ static void mtk_dsi_ps_control(struct mtk_dsi
> *dsi)
>  		dsi_tmp_buf_bpp = 3;
>  		break;
>  	case MIPI_DSI_FMT_RGB666:
> -		tmp_reg = LOOSELY_PS_18BIT_RGB666;
> +		tmp_reg = LOOSELY_PS_24BIT_RGB666;
>  		dsi_tmp_buf_bpp = 3;
>  		break;
>  	case MIPI_DSI_FMT_RGB666_PACKED: