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Message-ID: <554448a9-bc65-7c0b-9878-fb2c0fe9bfe4@molgen.mpg.de>
Date:   Wed, 9 Feb 2022 07:23:21 +0100
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Subject: Re: [PATCH v1] media: aspeed: Fix incorrect color
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To:     Jammy Huang <jammy_huang@aspeedtech.com>
References: <20220209024312.2218-1-jammy_huang@aspeedtech.com>
Cc:     eajames@linux.ibm.com, mchehab@kernel.org, joel@jms.id.au,
        andrew@aj.id.au, linux-media@vger.kernel.org,
        openbmc@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org,
        linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org
From:   Paul Menzel <pmenzel@molgen.mpg.de>
In-Reply-To: <20220209024312.2218-1-jammy_huang@aspeedtech.com>
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Dear Jammy,


Am 09.02.22 um 03:43 schrieb Jammy Huang:
> Current settings for rgb-2-yuv is BT.601(studio swing), but JFIF
> uses BT.601(full swing).

Could you please describe the problem in a little more detail? On an 
attached monitor to the BMC (which one) what incorrect colors are seen?

Maybe use:

> media: aspeed: Use full swing for JFIF to fix incorrect color

> Signed-off-by: Jammy Huang <jammy_huang@aspeedtech.com>
> ---
>   drivers/media/platform/aspeed-video.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/media/platform/aspeed-video.c b/drivers/media/platform/aspeed-video.c
> index eb9c17ac0e14..08b63b8297f0 100644
> --- a/drivers/media/platform/aspeed-video.c
> +++ b/drivers/media/platform/aspeed-video.c
> @@ -1089,7 +1089,7 @@ static void aspeed_video_init_regs(struct aspeed_video *video)
>   	u32 comp_ctrl = VE_COMP_CTRL_RSVD |
>   		FIELD_PREP(VE_COMP_CTRL_DCT_LUM, video->jpeg_quality) |
>   		FIELD_PREP(VE_COMP_CTRL_DCT_CHR, video->jpeg_quality | 0x10);
> -	u32 ctrl = VE_CTRL_AUTO_OR_CURSOR;
> +	u32 ctrl = VE_CTRL_AUTO_OR_CURSOR | VE_CTRL_YUV;

Excuse my ignorance, but reading [1][2] YUV can be represented by studio 
and full swing. How is the register/bit described in the datasheet, and 
can the macro name be improved?

>   	u32 seq_ctrl = video->jpeg_mode;
>   
>   	if (video->frame_rate)


Kind regards,

Paul


[1]: https://mymusing.co/bt601-yuv-to-rgb-conversion-color/
[2]: https://www.hisour.com/yuv-color-system-25916/