Re: [PATCH v2] drm/mediatek: dsi: fix scrolling of panel with small hfp or hbp

[Chun-Kuang Hu]

Hi, Jitao:

Jitao Shi <jitao.shi@xxxxxxxxxxxx> 於 2020年8月17日 週一 下午9:07寫道：
>
> horizontal_backporch_byte should be hbp * bpp - hbp extra bytes.
> So remove the wrong subtraction 10.
>
> Signed-off-by: Jitao Shi <jitao.shi@xxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 270bf22c98fe..5d031e634571 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -473,14 +473,13 @@ static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi)
>         horizontal_sync_active_byte = (vm->hsync_len * dsi_tmp_buf_bpp - 10);

So this subtraction 10 is correct?

Regards,
Chun-Kuang.

>
>         if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
> -               horizontal_backporch_byte =
> -                       (vm->hback_porch * dsi_tmp_buf_bpp - 10);
> +               horizontal_backporch_byte = vm->hback_porch * dsi_tmp_buf_bpp;
>         else
> -               horizontal_backporch_byte = ((vm->hback_porch + vm->hsync_len) *
> -                       dsi_tmp_buf_bpp - 10);
> +               horizontal_backporch_byte = (vm->hback_porch + vm->hsync_len) *
> +                                           dsi_tmp_buf_bpp;
>
>         data_phy_cycles = timing->lpx + timing->da_hs_prepare +
> -                         timing->da_hs_zero + timing->da_hs_exit + 3;
> +                         timing->da_hs_zero + timing->da_hs_exit;
>
>         if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) {
>                 if ((vm->hfront_porch + vm->hback_porch) * dsi_tmp_buf_bpp >
> --
> 2.12.5
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