linux-kernel - Re: [PATCH v4 2/9] drm/mediatek: dsi: Fix DSI RGB666 formats and definitions

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Message-ID: <06d0f56f-c27f-4d6a-9a88-e2932de29bf3@baylibre.com>
Date: Tue, 6 Feb 2024 15:51:38 +0100
From: Alexandre Mergnat <amergnat@...libre.com>
To: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
 chunkuang.hu@...nel.org
Cc: fshao@...omium.org, p.zabel@...gutronix.de, airlied@...il.com,
 daniel@...ll.ch, matthias.bgg@...il.com, dri-devel@...ts.freedesktop.org,
 linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, kernel@...labora.com
Subject: Re: [PATCH v4 2/9] drm/mediatek: dsi: Fix DSI RGB666 formats and
 definitions

Reviewed-by: Alexandre Mergnat <amergnat@...libre.com>

On 06/02/2024 13:07, 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

-- 
Regards,
Alexandre