linux-kernel - Re: [PATCH v5 2/6] drm/msm/dpu: adjust data width for widen bus case

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Date: Tue, 28 May 2024 16:07:17 -0700
From: Jessica Zhang <quic_jesszhan@...cinc.com>
To: Jun Nie <jun.nie@...aro.org>, Rob Clark <robdclark@...il.com>,
        "Abhinav
 Kumar" <quic_abhinavk@...cinc.com>,
        Dmitry Baryshkov
	<dmitry.baryshkov@...aro.org>,
        Sean Paul <sean@...rly.run>,
        Marijn Suijten
	<marijn.suijten@...ainline.org>,
        David Airlie <airlied@...il.com>, "Daniel
 Vetter" <daniel@...ll.ch>,
        Vinod Koul <vkoul@...nel.org>
CC: <linux-arm-msm@...r.kernel.org>, <dri-devel@...ts.freedesktop.org>,
        <freedreno@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 2/6] drm/msm/dpu: adjust data width for widen bus case



On 5/27/2024 7:21 AM, Jun Nie wrote:
> data is valid for only half the active window if widebus
> is enabled
> 
> Signed-off-by: Jun Nie <jun.nie@...aro.org>

Hi Jun,

Reviewed-by: Jessica Zhang <quic_jesszhan@...cinc.com>

Thanks,

Jessica Zhang

> ---
>   drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c | 9 +++++++++
>   1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
> index 225c1c7768ff..f97221423249 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
> @@ -168,6 +168,15 @@ static void dpu_hw_intf_setup_timing_engine(struct dpu_hw_intf *intf,
>   
>   	data_width = p->width;
>   
> +	/*
> +	 * If widebus is enabled, data is valid for only half the active window
> +	 * since the data rate is doubled in this mode. But for the compression
> +	 * mode in DP case, the p->width is already adjusted in
> +	 * drm_mode_to_intf_timing_params()
> +	 */
> +	if (p->wide_bus_en && !dp_intf)
> +		data_width = p->width >> 1;
> +
>   	hsync_data_start_x = hsync_start_x;
>   	hsync_data_end_x =  hsync_start_x + data_width - 1;
>   
> 
> -- 
> 2.34.1
>