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

[Yongqiang Niu]

On Thu, 2020-12-10 at 23:50 +0800, Chun-Kuang Hu wrote:
> Hi, Yongqiang:
> 
> Yongqiang Niu <yongqiang.niu@xxxxxxxxxxxx> 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@xxxxxxxxxxxx>
> > ---
> >  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.

how about this:
threshold = max(width * height * vrefresh * 4 * 7 / 1000000,
rdma_fifo_size);
> 
> > +
> >         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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