linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
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 <dri-devel@lists.freedesktop.org>,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>,
	linux-clk <linux-clk@vger.kernel.org>,
	Michael Trimarchi <michael@amarulasolutions.com>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	devicetree <devicetree@vger.kernel.org>,
	linux-kernel <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: Tue, 27 Nov 2018 11:24:50 +0100	[thread overview]
Message-ID: <20181127102450.b65jzhrdpxn5rxmk@flea> (raw)
In-Reply-To: <CAMty3ZCUOJmvekupOwh281g5HaazTpBbukWQY2Pv2OYypAwciw@mail.gmail.com>

[-- Attachment #1: Type: text/plain, Size: 3536 bytes --]

On Tue, Nov 20, 2018 at 09:55:42PM +0530, Jagan Teki wrote:
> On Tue, Nov 20, 2018 at 9:27 PM Maxime Ripard <maxime.ripard@bootlin.com> wrote:
> >
> > On Thu, Nov 15, 2018 at 11:19:53PM +0530, Jagan Teki wrote:
> > > On Thu, Nov 15, 2018 at 3:26 PM Maxime Ripard <maxime.ripard@bootlin.com> wrote:
> > > >
> > > > 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.
> > >
> > > Strange, VBP is earlier gives front porch which is anyway wrong.
> > >
> > > >
> > > > 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".
> > >
> > > W/o this 2-lane panel is breaking, same vblank timeout and visual
> > > artifacts at the bottom of the panel. though the commits may reference
> > > BSP, I have at-least tested on 3 different panels for us to prove its
> > > working.
> > >
> > > > Having some datasheet for the panels you had working would help too.
> > >
> > > Unfortunately datasheet doesn't have any required information what we
> > > actually looking for.
> >
> > Not even the timings? How did you get that information then?
> 
> datasheet has timing values, but this changes need controller
> information about VBP register that I don't have. But again existing
> VBP is not back porch for real, it's front porch.

Yet, this breaks the existing setup. So again:

> > > > 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".

Maxime

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

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]

  parent reply	other threads:[~2018-11-27 10:25 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
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 [this message]
2018-11-27 11:04             ` 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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20181127102450.b65jzhrdpxn5rxmk@flea \
    --to=maxime.ripard@bootlin.com \
    --cc=airlied@linux.ie \
    --cc=anarsoul@gmail.com \
    --cc=catalin.marinas@arm.com \
    --cc=devicetree@vger.kernel.org \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=icenowy@aosc.io \
    --cc=jagan@amarulasolutions.com \
    --cc=jernej.skrabec@siol.net \
    --cc=linux-amarula@amarulasolutions.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-clk@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-sunxi@googlegroups.com \
    --cc=mark.rutland@arm.com \
    --cc=michael@amarulasolutions.com \
    --cc=mturquette@baylibre.com \
    --cc=robh+dt@kernel.org \
    --cc=sboyd@kernel.org \
    --cc=wens@csie.org \
    --cc=will.deacon@arm.com \
    --subject='Re: [PATCH v4 08/26] drm/sun4i: sun6i_mipi_dsi: Fix VBP size calculation' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).