From mboxrd@z Thu Jan 1 00:00:00 1970 From: YT Shen Subject: Re: [PATCH v2 18/25] drm/mediatek: add RDMA fifo size error handle Date: Tue, 16 Apr 2019 19:31:24 +0800 Message-ID: <1555414284.27572.17.camel@mtksdaap41> References: <1553667561-25447-1-git-send-email-yongqiang.niu@mediatek.com> <1553667561-25447-19-git-send-email-yongqiang.niu@mediatek.com> <1555401647.11519.2.camel@mtksdaap41> <1555403837.31200.31.camel@mhfsdcap03> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1555403837.31200.31.camel@mhfsdcap03> Sender: linux-kernel-owner@vger.kernel.org To: yongqiang.niu@mediatek.com Cc: CK Hu , p.zabel@pengutronix.de, robh+dt@kernel.org, matthias.bgg@gmail.com, airlied@linux.ie, mark.rutland@arm.com, dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, Bibby.Hsieh@mediatek.com List-Id: dri-devel@lists.freedesktop.org On Tue, 2019-04-16 at 16:37 +0800, Yongqiang Niu wrote: > On Tue, 2019-04-16 at 16:00 +0800, CK Hu wrote: > > Hi, Yongqiang: > > > > On Wed, 2019-03-27 at 14:19 +0800, yongqiang.niu@mediatek.com wrote: > > > From: Yongqiang Niu > > > > > > This patch add RDMA fifo size error handle > > > rdma fifo size will not always bigger than the calculated threshold > > > if that case happened, we need set fifo size as the threshold > > > > > > Signed-off-by: Yongqiang Niu > > > --- > > > drivers/gpu/drm/mediatek/mtk_disp_rdma.c | 9 ++++++++- > > > 1 file changed, 8 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/gpu/drm/mediatek/mtk_disp_rdma.c b/drivers/gpu/drm/mediatek/mtk_disp_rdma.c > > > index b0a5cff..ead38ba 100644 > > > --- a/drivers/gpu/drm/mediatek/mtk_disp_rdma.c > > > +++ b/drivers/gpu/drm/mediatek/mtk_disp_rdma.c > > > @@ -137,11 +137,14 @@ static void mtk_rdma_config(struct mtk_ddp_comp *comp, unsigned int width, > > > { > > > unsigned int threshold; > > > unsigned int reg; > > > + unsigned int rdma_fifo_size; > > > struct mtk_disp_rdma *rdma = comp_to_rdma(comp); > > > > > > rdma_update_bits(comp, DISP_REG_RDMA_SIZE_CON_0, 0xfff, width); > > > rdma_update_bits(comp, DISP_REG_RDMA_SIZE_CON_1, 0xfffff, height); > > > > > > + rdma_fifo_size = RDMA_FIFO_SIZE(rdma); > > > + > > > /* > > > * Enable FIFO underflow since DSI and DPI can't be blocked. > > > * Keep the FIFO pseudo size reset default of 8 KiB. Set the > > > @@ -149,8 +152,12 @@ static void mtk_rdma_config(struct mtk_ddp_comp *comp, unsigned int width, > > > * account for blanking, and with a pixel depth of 4 bytes: > > > */ > > > threshold = width * height * vrefresh * 4 * 7 / 1000000; > > > + > > > + if (threshold > rdma_fifo_size) > > > + threshold = rdma_fifo_size; > > > > I think this is a work around not a correct solution. Why MT8173 has no > > this problem but MT8183 has? Is the formula of threshold different in > > MT8173 and MT8183? > > > > Regards, > > CK > > > > fifo size of RDMA0 and RDMA1 in MT8173 are same, which is SZ_8K. > this formula calculate result will not overflow if the screen size is > not big enough. > > but fifo size of RDMA1 in MT8183 only SZ_2K, if RDMA1 display with > solution 1080p60hz, this formula calculate result 3483 will overflow > SZ_2K. RDMA1 with SZ_2K can support up to 1080p60hz, even the formula shows overflow, is it correct? The formula shows all resolution something more than 1280x1080@60hz will overflow SZ_2K, and in this patch all set to maximum value. The patch should implement different FIFO size depends on RDMA0 (SZ_5K)and RDMA1 (SZ_2K), and use the value from the formula. Regards, yt.shen > > > > + > > > reg = RDMA_FIFO_UNDERFLOW_EN | > > > - RDMA_FIFO_PSEUDO_SIZE(RDMA_FIFO_SIZE(rdma)) | > > > + RDMA_FIFO_PSEUDO_SIZE(rdma_fifo_size) | > > > RDMA_OUTPUT_VALID_FIFO_THRESHOLD(threshold); > > > writel(reg, comp->regs + DISP_REG_RDMA_FIFO_CON); > > > } > > > > > >