Hi, CK,
Thanks for your review and comment.
On Mon, 2017-05-22 at 13:46 +0800, CK Hu wrote:
> Hi, Bibby:
>
> One comment inline.
>
> On Fri, 2017-05-19 at 17:57 +0800, Bibby Hsieh wrote:
> > For some greater resolution, the rdma threshold
> > variable will overflow.
> >
> > Signed-off-by: Bibby Hsieh <bibby.hsieh@xxxxxxxxxxxx>
> > ---
> > drivers/gpu/drm/mediatek/mtk_disp_rdma.c | 7 ++++---
> > 1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/mediatek/mtk_disp_rdma.c b/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
> > index 0df05f9..9afdcd7 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
> > @@ -37,7 +37,7 @@
> > #define DISP_REG_RDMA_FIFO_CON 0x0040
> > #define RDMA_FIFO_UNDERFLOW_EN BIT(31)
> > #define RDMA_FIFO_PSEUDO_SIZE(bytes) (((bytes) / 16) << 16)
> > -#define RDMA_OUTPUT_VALID_FIFO_THRESHOLD(bytes) ((bytes) / 16)
> > +#define RDMA_OUTPUT_VALID_FIFO_THRESHOLD(bytes) (((bytes) / 16) & 0x3ff)
>
> I think it's not necessary to do this mask operation. Before calling
> RDMA_OUTPUT_VALID_FIFO_THRESHOLD(), you should make sure that width,
> height, and vrefresh matches the HW spec, so the result of threshold
> likely does not exceed 0x3ff. If width, height, and vrefresh matches the
> HW spec but threshold exceed 0x3ff, maybe you should limited it to 0x3ff
> rather than truncating it.
>
Ok, It seems to me that I will refer Guenter's comment, add clamp_val()
to avoid unexpected value. Thanks.
Bibby
> Regards,
> CK
>
> >
> > /**
> > * struct mtk_disp_rdma - DISP_RDMA driver structure
> > @@ -109,7 +109,7 @@ static void mtk_rdma_config(struct mtk_ddp_comp *comp, unsigned int width,
> > unsigned int height, unsigned int vrefresh,
> > unsigned int bpc)
> > {
> > - unsigned int threshold;
> > + unsigned long long threshold;
> > unsigned int reg;
> >
> > rdma_update_bits(comp, DISP_REG_RDMA_SIZE_CON_0, 0xfff, width);
> > @@ -121,7 +121,8 @@ static void mtk_rdma_config(struct mtk_ddp_comp *comp, 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 = (unsigned long long)width * height * vrefresh *
> > + 4 * 7 / 1000000;
> > reg = RDMA_FIFO_UNDERFLOW_EN |
> > RDMA_FIFO_PSEUDO_SIZE(SZ_8K) |
> > RDMA_OUTPUT_VALID_FIFO_THRESHOLD(threshold);
>
>
--
Bibby
_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/dri-devel
