From: Nicolas Boichat <drinkcat@chromium.org>
To: Jitao Shi <jitao.shi@mediatek.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
Devicetree List <devicetree@vger.kernel.org>,
srv_heupstream <srv_heupstream@mediatek.com>,
David Airlie <airlied@linux.ie>,
huijuan.xie@mediatek.com, stonea168@163.com,
lkml <linux-kernel@vger.kernel.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
cawa cheng <cawa.cheng@mediatek.com>,
Rob Herring <robh+dt@kernel.org>,
"moderated list:ARM/Mediatek SoC support"
<linux-mediatek@lists.infradead.org>,
Daniel Vetter <daniel@ffwll.ch>,
Matthias Brugger <matthias.bgg@gmail.com>,
Yingjoe Chen <yingjoe.chen@mediatek.com>,
Eddie Huang <eddie.huang@mediatek.com>,
linux-arm Mailing List <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v5 1/1] drm/mediatek: dsi: fix scrolling of panel with small hfp or hbp
Date: Tue, 13 Oct 2020 18:54:05 +0800 [thread overview]
Message-ID: <CANMq1KBvG54ZW5gCzp4c_cpQjP6pZ9svngvvRUpWJn7FuMHt3Q@mail.gmail.com> (raw)
In-Reply-To: <20201013100625.13056-2-jitao.shi@mediatek.com>
On Tue, Oct 13, 2020 at 6:06 PM Jitao Shi <jitao.shi@mediatek.com> wrote:
>
> Replace horizontal_backporch_byte with vm->hback_porch * bpp to aovid
> flowing judgement negative number.
>
> if ((vm->hfront_porch * dsi_tmp_buf_bpp + horizontal_backporch_byte) >
> data_phy_cycles * dsi->lanes + delta)
>
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> ---
> drivers/gpu/drm/mediatek/mtk_dsi.c | 65 +++++++++++++++-----------------------
> 1 file changed, 25 insertions(+), 40 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 80b7a082e874..ddddf69ebeaf 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -445,6 +445,7 @@ static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi)
> u32 horizontal_backporch_byte;
> u32 horizontal_frontporch_byte;
> u32 dsi_tmp_buf_bpp, data_phy_cycles;
> + u32 delta;
> struct mtk_phy_timing *timing = &dsi->phy_timing;
>
> struct videomode *vm = &dsi->vm;
> @@ -466,50 +467,34 @@ static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi)
> horizontal_sync_active_byte = (vm->hsync_len * dsi_tmp_buf_bpp - 10);
>
> if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
> - horizontal_backporch_byte = vm->hback_porch * dsi_tmp_buf_bpp;
> + horizontal_backporch_byte =
> + (vm->hback_porch * dsi_tmp_buf_bpp - 10);
These parentheses are not required, but it might be a little clearer to write:
(vm->hback_porch * dsi_tmp_buf_bpp) - 10;
> else
> - horizontal_backporch_byte = (vm->hback_porch + vm->hsync_len) *
> - dsi_tmp_buf_bpp;
> + horizontal_backporch_byte = ((vm->hback_porch + vm->hsync_len) *
> + dsi_tmp_buf_bpp - 10);
ditto:
((vm->hback_porch + vm->hsync_len) * dsi_tmp_buf_bpp) - 10;
But then, _maybe_ it's clearer to drop this hunk and just add this
below the if/else:
horizontal_backporch_byte -= 10;
>
> data_phy_cycles = timing->lpx + timing->da_hs_prepare +
> - timing->da_hs_zero + timing->da_hs_exit;
> -
> - if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) {
> - if ((vm->hfront_porch + vm->hback_porch) * dsi_tmp_buf_bpp >
> - data_phy_cycles * dsi->lanes + 18) {
> - horizontal_frontporch_byte =
> - vm->hfront_porch * dsi_tmp_buf_bpp -
> - (data_phy_cycles * dsi->lanes + 18) *
> - vm->hfront_porch /
> - (vm->hfront_porch + vm->hback_porch);
> -
> - horizontal_backporch_byte =
> - horizontal_backporch_byte -
> - (data_phy_cycles * dsi->lanes + 18) *
> - vm->hback_porch /
> - (vm->hfront_porch + vm->hback_porch);
> - } else {
> - DRM_WARN("HFP less than d-phy, FPS will under 60Hz\n");
> - horizontal_frontporch_byte = vm->hfront_porch *
> - dsi_tmp_buf_bpp;
> - }
> + timing->da_hs_zero + timing->da_hs_exit + 3;
(for reference, apart from this `+ 3`, there is no functional change
in this hunk: this just moves delta outside of the if/else block,
which is a good idea for readability)
> +
> + delta = (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) ? 18 : 12;
> +
> + if ((vm->hfront_porch * dsi_tmp_buf_bpp + horizontal_backporch_byte) >
> + data_phy_cycles * dsi->lanes + delta) {
> + horizontal_frontporch_byte =
> + vm->hfront_porch * dsi_tmp_buf_bpp -
> + (data_phy_cycles * dsi->lanes + delta) *
> + vm->hfront_porch /
> + (vm->hfront_porch + vm->hback_porch);
> +
> + horizontal_backporch_byte =
> + horizontal_backporch_byte -
> + (data_phy_cycles * dsi->lanes + delta) *
> + vm->hback_porch /
> + (vm->hfront_porch + vm->hback_porch);
> } else {
> - if ((vm->hfront_porch + vm->hback_porch) * dsi_tmp_buf_bpp >
> - data_phy_cycles * dsi->lanes + 12) {
> - horizontal_frontporch_byte =
> - vm->hfront_porch * dsi_tmp_buf_bpp -
> - (data_phy_cycles * dsi->lanes + 12) *
> - vm->hfront_porch /
> - (vm->hfront_porch + vm->hback_porch);
> - horizontal_backporch_byte = horizontal_backporch_byte -
> - (data_phy_cycles * dsi->lanes + 12) *
> - vm->hback_porch /
> - (vm->hfront_porch + vm->hback_porch);
> - } else {
> - DRM_WARN("HFP less than d-phy, FPS will under 60Hz\n");
> - horizontal_frontporch_byte = vm->hfront_porch *
> - dsi_tmp_buf_bpp;
> - }
> + DRM_WARN("HFP + HBP less than d-phy, FPS will under 60Hz\n");
> + horizontal_frontporch_byte = vm->hfront_porch *
> + dsi_tmp_buf_bpp;
> }
>
> writel(horizontal_sync_active_byte, dsi->regs + DSI_HSA_WC);
> --
> 2.12.5
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
_______________________________________________
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next prev parent reply other threads:[~2020-10-13 10:54 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-13 10:06 [PATCH v5 0/1] fix scrolling of panel with small hfp or hbp Jitao Shi
2020-10-13 10:06 ` [PATCH v5 1/1] drm/mediatek: dsi: " Jitao Shi
2020-10-13 10:54 ` Nicolas Boichat [this message]
2020-10-29 13:22 ` Chun-Kuang Hu
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