Hi, Yongqiang: On Mon, 2021-04-12 at 15:25 +0800, Yongqiang Niu wrote: > the orginal formula will caused rdma fifo threshold config overflow > > Signed-off-by: Yongqiang Niu <yongqiang.niu@xxxxxxxxxxxx> > --- > drivers/gpu/drm/mediatek/mtk_disp_rdma.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/mediatek/mtk_disp_rdma.c b/drivers/gpu/drm/mediatek/mtk_disp_rdma.c > index 728aaad..8c9371b 100644 > --- a/drivers/gpu/drm/mediatek/mtk_disp_rdma.c > +++ b/drivers/gpu/drm/mediatek/mtk_disp_rdma.c > @@ -167,7 +167,7 @@ void mtk_rdma_config(struct device *dev, unsigned int width, > * output threshold to 6 microseconds with 7/6 overhead to > * account for blanking, and with a pixel depth of 4 bytes: > */ > - threshold = width * height * vrefresh * 4 * 7 / 1000000; > + threshold = rdma_fifo_size * 7 / 10; It's better to set threshold by width and height, but it seems that no one could come out a solution for all SoC. I could just accept this solution, but I need some addition comment for this solution. How do you decide 7/10? In the future, another may need to modify this value and he need to know why you use 7/10. If you just choose it at random, just tell us that you just randomly choose it. Regards, CK > reg = RDMA_FIFO_UNDERFLOW_EN | > RDMA_FIFO_PSEUDO_SIZE(rdma_fifo_size) | > RDMA_OUTPUT_VALID_FIFO_THRESHOLD(threshold);
