Hi, Hsin-Yi:
On Thu, 2021-01-28 at 19:23 +0800, Hsin-Yi Wang wrote:
> From: Yongqiang Niu <yongqiang.niu@xxxxxxxxxxxx>
>
> for 5 or 6 bpc panel, we need enable dither function
> to improve the display quality
>
> Signed-off-by: Yongqiang Niu <yongqiang.niu@xxxxxxxxxxxx>
> Signed-off-by: Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx>
> ---
> drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c | 15 +++++++++++++--
> 1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> index ac2cb25620357..6c8f246380a74 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> @@ -53,6 +53,7 @@
> #define DITHER_EN BIT(0)
> #define DISP_DITHER_CFG 0x0020
> #define DITHER_RELAY_MODE BIT(0)
> +#define DITHER_ENGINE_EN BIT(1)
> #define DISP_DITHER_SIZE 0x0030
>
> #define LUT_10BIT_MASK 0x03ff
> @@ -314,9 +315,19 @@ static void mtk_dither_config(struct device *dev, unsigned int w,
> unsigned int bpc, struct cmdq_pkt *cmdq_pkt)
> {
> struct mtk_ddp_comp_dev *priv = dev_get_drvdata(dev);
> + bool enable = (bpc == 5 || bpc == 6);
I strongly believe that dither function in dither is identical to the
one in gamma and od, and in mtk_dither_set_common(), 'bpc >=
MTK_MIN_BPC' is valid, so I believe we need not to limit bpc to 5 or 6.
But we should consider the case that bpc is invalid in
mtk_dither_set_common(). Invalid case in gamma and od use different way
to process. For gamma, dither is default relay mode, so invalid bpc
would do nothing in mtk_dither_set_common() and result in relay mode.
For od, it set to relay mode first, them invalid bpc would do nothing in
mtk_dither_set_common() and result in relay mode. I would like dither,
gamma and od to process invalid bpc in the same way. One solution is to
set relay mode in mtk_dither_set_common() for invalid bpc.
Regards,
CK
>
> - mtk_ddp_write(cmdq_pkt, h << 16 | w, &priv->cmdq_reg, priv->regs, DISP_DITHER_SIZE);
> - mtk_ddp_write(cmdq_pkt, DITHER_RELAY_MODE, &priv->cmdq_reg, priv->regs, DISP_DITHER_CFG);
> + if (enable) {
> + mtk_dither_set_common(priv->regs, &priv->cmdq_reg, bpc,
> + DISP_DITHER_CFG, DITHER_ENGINE_EN,
> + cmdq_pkt);
> + } else {
> + mtk_ddp_write(cmdq_pkt, DITHER_RELAY_MODE, &priv->cmdq_reg,
> + priv->regs, DISP_DITHER_CFG);
> + }
> +
> + mtk_ddp_write(cmdq_pkt, h << 16 | w, &priv->cmdq_reg, priv->regs,
> + DISP_DITHER_SIZE);
> }
>
> static void mtk_dither_start(struct device *dev)
