[PATCH v10 3/9] drm/mediatek: add RDMA fifo size error handle

[CK Hu]

Hi, Hsin-Yi:

On Wed, 2021-01-27 at 12:54 +0800, Hsin-Yi Wang wrote:
> From: Yongqiang Niu <yongqiang.niu at mediatek.com>
> 
> 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 at mediatek.com>
> Signed-off-by: Hsin-Yi Wang <hsinyi at chromium.org>
> ---
>  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 b84004394970f..04b9542010b00 100644
> --- a/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
> +++ b/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
> @@ -168,6 +168,10 @@ void mtk_rdma_config(struct device *dev, 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;

Please see the discussion in [1].

[1]
https://patchwork.kernel.org/project/linux-mediatek/patch/1607591262-21736-6-git-send-email-yongqiang.niu@mediatek.com/

Regards,
CK

> +
>  	reg = RDMA_FIFO_UNDERFLOW_EN |
>  	      RDMA_FIFO_PSEUDO_SIZE(rdma_fifo_size) |
>  	      RDMA_OUTPUT_VALID_FIFO_THRESHOLD(threshold);