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From: Maxime Ripard <maxime.ripard@bootlin.com>
To: Jagan Teki <jagan@amarulasolutions.com>
Cc: Chen-Yu Tsai <wens@csie.org>, Icenowy Zheng <icenowy@aosc.io>,
	Jernej Skrabec <jernej.skrabec@siol.net>,
	Vasily Khoruzhick <anarsoul@gmail.com>,
	Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	David Airlie <airlied@linux.ie>,
	dri-devel@lists.freedesktop.org,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>,
	linux-clk@vger.kernel.org,
	Michael Trimarchi <michael@amarulasolutions.com>,
	linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com,
	linux-amarula@amarulasolutions.com
Subject: Re: [PATCH v4 08/26] drm/sun4i: sun6i_mipi_dsi: Fix VBP size calculation
Date: Thu, 15 Nov 2018 10:55:51 +0100	[thread overview]
Message-ID: <20181115095551.uctdkfmuwlnzhjnn@flea> (raw)
In-Reply-To: <20181113111633.20189-9-jagan@amarulasolutions.com>

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Hi,

On Tue, Nov 13, 2018 at 04:46:15PM +0530, Jagan Teki wrote:
> The horizontal and vertical back porch calculation in BSP
> code is simply following the Linux drm comment diagram, in
> include/drm/drm_modes.h which is
> 
> [hv]back porch = [hv]total - [hv]sync_end
> 
> BSP code form BPI-M64-bsp is calculating vertical back porch as
> (from linux-sunxi/drivers/video/sunxi/disp2/disp/de/disp_lcd.c)
> 
> timmings->ver_sync_time= panel_info->lcd_vspw;
> timmings->ver_back_porch= panel_info->lcd_vbp-panel_info->lcd_vspw;
> 
> vbp = panel->lcd_vbp;
> vspw = panel->lcd_vspw;
> dsi_dev[sel]->dsi_basic_size0.bits.vbp = vbp-vspw;
> dsi_dev[sel]->dsi_basic_size0.bits.vbp = panel->lcd_vbp - panel->lcd_vspw;
> =>  timmings->ver_back_porch + panel_info->lcd_vspw - panel_info->lcd_vspw
> =>  timmings->ver_back_porch
> =>  mode->vtotal - mode->end
> 
> Which evatually same as mode->vtotal - mode->vsync_end so update the
> same in SUN6I_DSI_BASIC_SIZE0_VBP
> 
> On the information note, existing SUN6I_DSI_BASIC_SIZE0_VSA is proper
> value.
> 
> Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>

I've tested your changes on my A33 board, and this commit will break
it.

It creates vblank timeouts, and visual artifacts at the bottom of the
display.

Later commits seem to fix the issue, but will create some blanking on
the upper third of the display.

Since the documentation is quite sparse, and a MIPI-DSI analyzer is
way too expensive, I'd really like to have at least what each of these
commits are actually fixing, and what symptoms each of these were
causing, and not just "the BSP does it".

Having some datasheet for the panels you had working would help too.

Maxime

-- 
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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  reply	other threads:[~2018-11-15  9:56 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-13 11:16 [PATCH v4 00/26] drm/sun4i: Allwinner A64 MIPI-DSI support Jagan Teki
2018-11-13 11:16 ` [PATCH v4 01/26] clk: sunxi-ng: a64: Fix gate bit of DSI DPHY Jagan Teki
2018-11-13 13:08   ` Maxime Ripard
2018-11-13 11:16 ` [PATCH v4 02/26] clk: sunxi-ng: Add check for minimal rate to NKM PLLs Jagan Teki
2018-11-13 11:16 ` [PATCH v4 03/26] clk: sunxi-ng: Add check for maximum " Jagan Teki
2018-11-13 13:26   ` Maxime Ripard
2018-11-15 15:21     ` Jagan Teki
2018-11-20 10:55       ` Maxime Ripard
2018-11-20 12:07         ` Jagan Teki
2018-11-13 11:16 ` [PATCH v4 04/26] drm/sun4i: sun6i_mipi_dsi: Add has_mod_clk quirk Jagan Teki
2018-11-13 11:16 ` [PATCH v4 05/26] drm/sun4i: sun6i_mipi_dsi: Add Allwinner A64 MIPI DSI support Jagan Teki
2018-11-13 11:16 ` [PATCH v4 06/26] dt-bindings: sun6i-dsi: Add compatible for A64 MIPI DSI Jagan Teki
2018-11-13 11:16 ` [PATCH v4 07/26] drm/sun4i: sun6i_mipi_dsi: Add DSI Generic short write 2 param transfer Jagan Teki
2018-11-13 11:16 ` [PATCH v4 08/26] drm/sun4i: sun6i_mipi_dsi: Fix VBP size calculation Jagan Teki
2018-11-15  9:55   ` Maxime Ripard [this message]
2018-11-15 17:49     ` Jagan Teki
2018-11-20 15:57       ` Maxime Ripard
2018-11-20 16:25         ` Jagan Teki
2018-11-26 12:07           ` [linux-sunxi] " Jagan Teki
2018-11-27 10:25             ` Maxime Ripard
2018-11-27 10:24           ` Maxime Ripard
2018-11-27 11:04             ` [linux-sunxi] " Jagan Teki
2018-12-07 13:21               ` Maxime Ripard
2018-12-10 16:07                 ` Jagan Teki
2018-11-13 11:16 ` [PATCH v4 09/26] drm/sun4i: sun6i_mipi_dsi: Fix TCON DRQ set bits Jagan Teki
2018-11-13 11:16 ` [PATCH v4 10/26] drm/sun4i: sun6i_mipi_dsi: Refactor vertical video start delay Jagan Teki
2018-11-13 11:16 ` [PATCH v4 11/26] drm/sun4i: sun6i_mipi_dsi: Fix DSI hbp timing value Jagan Teki
2018-11-13 11:16 ` [PATCH v4 12/26] drm/sun4i: sun6i_mipi_dsi: Fix DSI hblk timing calculation Jagan Teki
2018-11-13 11:16 ` [PATCH v4 13/26] drm/sun4i: sun6i_mipi_dsi: Add DSI hblk packet overhead Jagan Teki
2018-11-13 11:16 ` [PATCH v4 14/26] drm/sun4i: sun6i_mipi_dsi: Fix DSI hfp timing value Jagan Teki
2018-11-13 11:16 ` [PATCH v4 15/26] drm/sun4i: sun6i_mipi_dsi: Set proper vblk timing calculation Jagan Teki
2018-11-13 11:16 ` [PATCH v4 16/26] drm/sun4i: sun6i_mipi_dsi: Add support for VCC-DSI voltage regulator Jagan Teki
2018-11-13 11:16 ` [PATCH v4 17/26] dt-bindings: sun6i-dsi: Add VCC-DSI supply property Jagan Teki
2018-11-16 23:19   ` Rob Herring
2018-11-13 11:16 ` [PATCH v4 18/26] dt-bindings: panel: Add Bananapi S070WV20-CT16 ICN6211 MIPI-DSI to RGB bridge Jagan Teki
2018-11-13 11:16 ` [PATCH v4 19/26] drm/panel: " Jagan Teki
2018-11-13 11:16 ` [PATCH v4 20/26] dt-bindings: panel: Add Techstar TS8550B MIPI-DSI panel Jagan Teki
2018-11-13 11:16 ` [PATCH v4 21/26] drm/panel: Add Techstar TS8550B MIPI-DSI LCD panel Jagan Teki
2018-11-13 11:16 ` [PATCH v4 22/26] clk: sunxi-ng: a64: Add min and max rate for PLL_MIPI Jagan Teki
2018-11-13 11:16 ` [PATCH v4 23/26] dt-bindings: sun6i-dsi: Add compatible for A64 DPHY Jagan Teki
2018-11-13 11:16 ` [PATCH v4 24/26] arm64: dts: allwinner: a64: Add DSI pipeline Jagan Teki
2018-11-13 11:16 ` [PATCH v4 25/26] [DO NOT MERGE] arm64: dts: allwinner: bananapi-m64: Bananapi S070WV20-CT16 DSI panel Jagan Teki
2018-11-13 12:22   ` Andre Przywara
2018-11-14  6:31     ` Jagan Teki
2018-11-14  6:58       ` Chen-Yu Tsai
2018-11-14  9:22         ` Chen-Yu Tsai
2018-11-14 11:18           ` Jagan Teki
2018-11-13 11:16 ` [PATCH v4 26/26] arm64: dts: allwinner: a64-amarula-relic: Enable Techstar TS8550B MIPI-DSI panel Jagan Teki
2018-11-13 12:32   ` Andre Przywara

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