Re: [PATCH v11 7/9] drm/mediatek: enable dither function

CK Hu
2021-01-28T07:43:12Z

Hi, Hsin-Yi:

On Thu, 2021-01-28 at 15:28 +0800, Hsin-Yi Wang wrote:
> From: Yongqiang Niu <yongqiang.niu@mediatek.com>
>
> for 5 or 6 bpc panel, we need enable dither function
> to improve the display quality
>
> Signed-off-by: Yongqiang Niu <yongqiang.niu@mediatek.com>
> Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
> ---
> drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c | 44 ++++++++++++++++++++-
> 1 file changed, 43 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> index 8173f709272be..e85625704d611 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> @@ -53,7 +53,9 @@
> #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 DITHER_REG(idx) (0x100 + (idx) * 4)
>
> #define LUT_10BIT_MASK 0x03ff
>
> @@ -313,8 +315,48 @@ static void mtk_dither_config(struct device *dev, unsigned int w,
> {
> struct mtk_ddp_comp_dev *priv = dev_get_drvdata(dev);
>
> + bool enable = false;
> +
> + /* default value for dither reg 5 to 14 */
> + const u32 dither_setting[] = {
> + 0x00000000, /* 5 */
> + 0x00003002, /* 6 */
> + 0x00000000, /* 7 */
> + 0x00000000, /* 8 */
> + 0x00000000, /* 9 */
> + 0x00000000, /* 10 */
> + 0x00000000, /* 11 */
> + 0x00000011, /* 12 */
> + 0x00000000, /* 13 */
> + 0x00000000, /* 14 */

Could you explain what is this?

> + };
> +
> + if (bpc == 5 || bpc == 6) {
> + enable = true;
> + mtk_ddp_write(cmdq_pkt,
> + DITHER_LSB_ERR_SHIFT_R(MTK_MAX_BPC - bpc) |
> + DITHER_ADD_LSHIFT_R(MTK_MAX_BPC - bpc) |
> + DITHER_NEW_BIT_MODE,
> + &priv->cmdq_reg, priv->regs, DITHER_REG(15));
> + mtk_ddp_write(cmdq_pkt,
> + DITHER_LSB_ERR_SHIFT_B(MTK_MAX_BPC - bpc) |
> + DITHER_ADD_LSHIFT_B(MTK_MAX_BPC - bpc) |
> + DITHER_LSB_ERR_SHIFT_G(MTK_MAX_BPC - bpc) |
> + DITHER_ADD_LSHIFT_G(MTK_MAX_BPC - bpc),

This result in 0x50505050, but previous version is 0x50504040, so this
version is correct and previous version is incorrect?

Regards,
CK

> + &priv->cmdq_reg, priv->regs, DITHER_REG(16));
> + }
> +
> +
> + if (enable) {
> + u32 idx;
> +
> + for (idx = 0; idx < ARRAY_SIZE(dither_setting); idx++)
> + mtk_ddp_write(cmdq_pkt, dither_setting[idx], &priv->cmdq_reg, priv->regs,
> + DITHER_REG(idx + 5));
> + }
> +
> 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);
> + mtk_ddp_write(cmdq_pkt, enable ? DITHER_ENGINE_EN : DITHER_RELAY_MODE, &priv->cmdq_reg, priv->regs, DISP_DITHER_CFG);
> }
>
> static void mtk_dither_start(struct device *dev)