From mboxrd@z Thu Jan 1 00:00:00 1970 From: ck.hu@mediatek.com (CK Hu) Date: Mon, 12 Sep 2016 11:15:42 +0800 Subject: [PATCH v4 3/3] drm/mediatek: fix the wrong pixel clock when resolution is 4K In-Reply-To: <1471417088-2993-4-git-send-email-bibby.hsieh@mediatek.com> References: <1471417088-2993-1-git-send-email-bibby.hsieh@mediatek.com> <1471417088-2993-4-git-send-email-bibby.hsieh@mediatek.com> Message-ID: <1473650142.28437.5.camel@mtksdaap41> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, Bibby: Sorry for the late reply. On Wed, 2016-08-17 at 14:58 +0800, Bibby Hsieh wrote: > From: Junzhi Zhao > > Pixel clock should be 297MHz when resolution is 4K. > >>From the code you modified, I think title should be: "Enlarge pll_rate range from (, ) to (, )" In description, you can explain the pll_rate for 4K and this enlargement could support more resolution include 4K (Not only 4K). > Signed-off-by: Junzhi Zhao > Signed-off-by: Bibby Hsieh > --- > drivers/gpu/drm/mediatek/mtk_dpi.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c > index 0186e50..90fb831 100644 > --- a/drivers/gpu/drm/mediatek/mtk_dpi.c > +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c > @@ -432,11 +432,16 @@ static int mtk_dpi_set_display_mode(struct mtk_dpi *dpi, > unsigned long pll_rate; > unsigned int factor; > > + /* let pll_rate can fix the valid range of tvdpll (1G~2GHz) */ > pix_rate = 1000UL * mode->clock; > - if (mode->clock <= 74000) > + if (mode->clock <= 27000) > + factor = 16 * 3; > + else if (mode->clock <= 84000) > 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", Regards, CK