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 <linux-sunxi@googlegroups.com>
Subject: Re: [PATCH 08/12] drm/sun4i: sun6i_mipi_dsi: Refactor vertical video start delay
Date: Sat, 29 Sep 2018 17:27:58 +0200 [thread overview]
Message-ID: <20180929152758.g3goxwjud2ym5rft@flea> (raw)
In-Reply-To: <CAMty3ZDxpLwVDsgVMjX+6+uz89sQ1aZaXHHZ+-5aogrA4MHmqw@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 2206 bytes --]
On Thu, Sep 27, 2018 at 11:03:19PM +0530, Jagan Teki wrote:
> On Thu, Sep 27, 2018 at 10:44 PM Maxime Ripard
> <maxime.ripard@bootlin.com> wrote:
> >
> > On Thu, Sep 27, 2018 at 05:18:46PM +0530, Jagan Teki wrote:
> > > Accordingly to BPI-M64-bsp DE DSI code Video start delay
> > > can be computed by subtracting total vertical timing with
> > > front porch timing and with adding 1 delay line for TCON.
> >
> > This is what the current code is doing as well.
>
> The current code
> return mode->vtotal - (mode->vsync_end - mode->vdisplay) + 1;
>
> (mode->vsync_end - mode->vdisplay) = front porch + sync
>
> but I'm updating here only front porch.
>
> >
> > > This patch simply add the start_delay logic from BPI-M64-bsp,
> > > w/o this new computation, the DSI on A64 encounter vblank time out.
> > >
> > > [CRTC:36:crtc-0] vblank wait timed out
> > >
> > > Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
> > > ---
> > > drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 12 +++++++++++-
> > > 1 file changed, 11 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> > > index 9918fdb990ff..217db74c6dc3 100644
> > > --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> > > +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> > > @@ -358,7 +358,17 @@ static void sun6i_dsi_inst_init(struct sun6i_dsi *dsi,
> > > static u16 sun6i_dsi_get_video_start_delay(struct sun6i_dsi *dsi,
> > > struct drm_display_mode *mode)
> > > {
> > > - return mode->vtotal - (mode->vsync_end - mode->vdisplay) + 1;
> > > + u32 vfp = mode->vsync_start - mode->vdisplay;
>
> let me explain this.
>
> Actual code from Allwinner
> u32 vfp = panel->lcd_vt - panel->lcd_y - panel->lcd_vbp;
>
> So,
>
> => (panel->lcd_vt - panel->lcd_y) - (panel->lcd_vbp)
> => (front porch + sync + back porch) - (back porch + sync)
Unless Allwinner is doing something fishy, in which case that should
be mentionned, the back porch doesn't contain the sync pulse.
Maxime
--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
next prev parent reply other threads:[~2018-09-29 15:28 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-27 11:48 [PATCH 00/12] drm/sun4i: Allwinner A64 MIPI-DSI support Jagan Teki
2018-09-27 11:48 ` [PATCH 01/12] clk: sunxi-ng: a64: Fix gate bit of DSI DPHY Jagan Teki
2018-09-27 11:48 ` [PATCH 02/12] drm/sun4i: sun6i_mipi_dsi: Add Allwinner A64 MIPI DSI support Jagan Teki
2018-09-27 11:48 ` [PATCH 03/12] dt-bindings: sun6i-dsi: Add compatible for A64 MIPI DSI Jagan Teki
2018-10-15 18:24 ` Rob Herring
2018-09-27 11:48 ` [PATCH 04/12] drm/sun4i: sun6i_mipi_dsi: Enable missing DSI bus clock Jagan Teki
2018-09-27 12:42 ` Chen-Yu Tsai
2018-09-27 13:44 ` Jagan Teki
2018-09-27 14:16 ` [linux-sunxi] " Chen-Yu Tsai
2018-09-27 16:26 ` Jagan Teki
2018-09-27 16:33 ` Chen-Yu Tsai
2018-09-27 11:48 ` [PATCH 05/12] drm/sun4i: sun6i_mipi_dsi: Add DSI Generic short write 2 param transfer Jagan Teki
2018-09-27 17:18 ` Maxime Ripard
2018-09-27 17:36 ` Jagan Teki
2018-09-29 13:47 ` Maxime Ripard
2018-09-27 11:48 ` [PATCH 06/12] drm/sun4i: sun6i_mipi_dsi: Fix VBP size calculation Jagan Teki
2018-09-27 15:21 ` Maxime Ripard
2018-09-27 16:20 ` Jagan Teki
2018-09-29 13:53 ` Maxime Ripard
2018-10-01 8:09 ` [linux-sunxi] " Jagan Teki
2018-10-08 15:05 ` Maxime Ripard
2018-09-27 11:48 ` [PATCH 07/12] drm/sun4i: sun6i_mipi_dsi: Fix TCON DRQ set bits Jagan Teki
2018-09-27 16:58 ` Maxime Ripard
2018-09-27 17:45 ` Jagan Teki
2018-10-02 13:20 ` Maxime Ripard
2018-10-03 3:22 ` [linux-sunxi] " Jagan Teki
2018-10-08 15:05 ` Maxime Ripard
2018-09-27 11:48 ` [PATCH 08/12] drm/sun4i: sun6i_mipi_dsi: Refactor vertical video start delay Jagan Teki
2018-09-27 17:14 ` Maxime Ripard
2018-09-27 17:33 ` Jagan Teki
2018-09-29 15:27 ` Maxime Ripard [this message]
2018-10-01 7:55 ` [linux-sunxi] " Jagan Teki
2018-10-02 13:29 ` Maxime Ripard
2018-09-27 11:48 ` [PATCH 09/12] dt-bindings: panel: Add Bananapi S070WV20-CT16 MIPI-DSI panel bindings Jagan Teki
2018-10-15 18:24 ` Rob Herring
2018-10-22 10:22 ` Chen-Yu Tsai
2018-10-23 15:11 ` Rob Herring
2018-10-24 20:22 ` Chen-Yu Tsai
2018-09-27 11:48 ` [PATCH 10/12] drm/panel: Add Bananapi S070WV20-CT16 MIPI-DSI panel driver Jagan Teki
2018-09-28 4:32 ` Chen-Yu Tsai
2018-10-04 16:06 ` Jagan Teki
2018-09-27 11:48 ` [PATCH 11/12] arm64: dts: allwinner: a64: Add DSI pipeline Jagan Teki
2018-09-27 17:16 ` Maxime Ripard
2018-09-27 11:48 ` [PATCH 12/12] arm64: dts: allwinner: bananapi-m64: Bananapi S070WV20-CT16 DSI panel Jagan Teki
2018-09-27 17:17 ` Maxime Ripard
2018-10-04 16:03 ` Jagan Teki
2018-10-05 15:31 ` Maxime Ripard
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=20180929152758.g3goxwjud2ym5rft@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-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 \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
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).