Re: [PATCH v8, 5/6] drm/mediatek: add RDMA fifo size error handle

[Chun-Kuang Hu <chunkuang.hu@kernel.org>]

Hi, Yongqiang:

Yongqiang Niu <yongqiang.niu@mediatek.com> 於 2020年12月10日 週四 下午5:08寫道：
>
> This patch add RDMA fifo size error handle
> rdma fifo size will not always bigger than the calculated threshold
> if that case happened, we need set fifo size as the threshold
>
> Signed-off-by: Yongqiang Niu <yongqiang.niu@mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_disp_rdma.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_disp_rdma.c b/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
> index 794acc5..0508392 100644
> --- a/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
> +++ b/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
> @@ -151,6 +151,10 @@ static void mtk_rdma_config(struct mtk_ddp_comp *comp, unsigned int width,
>          * account for blanking, and with a pixel depth of 4 bytes:
>          */
>         threshold = width * height * vrefresh * 4 * 7 / 1000000;
> +
> +       if (threshold > rdma_fifo_size)
> +               threshold = rdma_fifo_size;

If the formula is not correct, you should fix the formula not work around.

Regards,
Chun-Kuang.

> +
>         reg = RDMA_FIFO_UNDERFLOW_EN |
>               RDMA_FIFO_PSEUDO_SIZE(rdma_fifo_size) |
>               RDMA_OUTPUT_VALID_FIFO_THRESHOLD(threshold);
> --
> 1.8.1.1.dirty
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