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From:   Jernej =?utf-8?B?xaBrcmFiZWM=?= <jernej.skrabec@siol.net>
To:     roman.stratiienko@globallogic.com
Cc:     linux-kernel@vger.kernel.org, mripard@kernel.org,
        dri-devel@lists.freedesktop.org
Subject: Re: drm/sun4i: Add missing pixel formats to the vi layer
Date:   Thu, 19 Sep 2019 20:53:10 +0200
Message-ID: <9229663.7SG9YZCNdo@jernej-laptop>
In-Reply-To: <20190918110541.38124-1-roman.stratiienko@globallogic.com>
References: <20190918110541.38124-1-roman.stratiienko@globallogic.com>
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Hi!

Dne sreda, 18. september 2019 ob 13:05:41 CEST je 
roman.stratiienko@globallogic.com napisal(a):
> From: Roman Stratiienko <roman.stratiienko@globallogic.com>
> 
> According to Allwinner DE2.0 Specification REV 1.0, vi layer supports the
> following pixel formats:  ABGR_8888, ARGB_8888, BGRA_8888, RGBA_8888

It's true that DE2 VI layers support those formats, but it wouldn't change 
anything because alpha blending is not supported by those planes. These 
formats were deliberately left out because their counterparts without alpha 
exist, for example ABGR8888 <-> XBGR8888. It would also confuse user, which 
would expect that alpha blending works if format with alpha channel is 
selected.

Admittedly some formats with alpha are still reported as supported due to lack 
of their counterparts without alpha, but I'm fine with removing them for 
consistency.

Best regards,
Jernej

> 
> Signed-off-by: Roman Stratiienko <roman.stratiienko@globallogic.com>
> ---
>  drivers/gpu/drm/sun4i/sun8i_vi_layer.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/gpu/drm/sun4i/sun8i_vi_layer.c
> b/drivers/gpu/drm/sun4i/sun8i_vi_layer.c index bd0e6a52d1d8..07c27e6a4b77
> 100644
> --- a/drivers/gpu/drm/sun4i/sun8i_vi_layer.c
> +++ b/drivers/gpu/drm/sun4i/sun8i_vi_layer.c
> @@ -404,17 +404,21 @@ static const struct drm_plane_funcs
> sun8i_vi_layer_funcs = { static const u32 sun8i_vi_layer_formats[] = {
>  	DRM_FORMAT_ABGR1555,
>  	DRM_FORMAT_ABGR4444,
> +	DRM_FORMAT_ABGR8888,
>  	DRM_FORMAT_ARGB1555,
>  	DRM_FORMAT_ARGB4444,
> +	DRM_FORMAT_ARGB8888,
>  	DRM_FORMAT_BGR565,
>  	DRM_FORMAT_BGR888,
>  	DRM_FORMAT_BGRA5551,
>  	DRM_FORMAT_BGRA4444,
> +	DRM_FORMAT_BGRA8888,
>  	DRM_FORMAT_BGRX8888,
>  	DRM_FORMAT_RGB565,
>  	DRM_FORMAT_RGB888,
>  	DRM_FORMAT_RGBA4444,
>  	DRM_FORMAT_RGBA5551,
> +	DRM_FORMAT_RGBA8888,
>  	DRM_FORMAT_RGBX8888,
>  	DRM_FORMAT_XBGR8888,
>  	DRM_FORMAT_XRGB8888,