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SubjectRe: [PATCH v3 3/3] drm/mediatek: fix the wrong pixel clock when resolution is 4K
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Am Donnerstag, den 04.08.2016, 10:38 +0800 schrieb Bibby Hsieh:
> From: Junzhi Zhao <junzhi.zhao@mediatek.com>
>
> Pixel clock should be 297MHz when resolution is 4K.
>
> Signed-off-by: Junzhi Zhao <junzhi.zhao@mediatek.com>
> Signed-off-by: Bibby Hsieh <bibby.hsieh@mediatek.com>
> ---
> drivers/gpu/drm/mediatek/mtk_dpi.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c
> index d05ca79..a90af59 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> @@ -438,10 +438,14 @@ static int mtk_dpi_set_display_mode(struct mtk_dpi *dpi,
> }
>
> pix_rate = 1000UL * mode->clock;
> - if (mode->clock <= 74000)
> + if (mode->clock <= 27000)
> + factor = 16 * 3;
> + else if (mode->clock <= 74250)
> factor = 8 * 3;
> - else
> + else if (mode->clock <= 167000)
> factor = 4 * 3;
> + else
> + factor = 2 * 3;
> pll_rate = pix_rate * factor;
>
> dev_dbg(dpi->dev, "Want PLL %lu Hz, pixel clock %lu Hz\n",

Could you add a comment why this also changes the 74 MHz limit to 74.25
MHz and that adds a factor 16*3 for clocks <= 27 MHz ?

regards
Philipp

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