From: Paul Boddie <paul@boddie.org.uk>
To: "H. Nikolaus Schaller" <hns@goldelico.com>
Cc: Paul Cercueil <paul@crapouillou.net>,
Mark Rutland <mark.rutland@arm.com>,
Geert Uytterhoeven <geert+renesas@glider.be>,
Neil Armstrong <narmstrong@baylibre.com>,
David Airlie <airlied@linux.ie>,
dri-devel <dri-devel@lists.freedesktop.org>,
linux-mips <linux-mips@vger.kernel.org>,
Andrzej Hajda <a.hajda@samsung.com>,
Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
Miquel Raynal <miquel.raynal@bootlin.com>,
Sam Ravnborg <sam@ravnborg.org>,
Jernej Skrabec <jernej.skrabec@gmail.com>,
Harry Wentland <harry.wentland@amd.com>,
OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS
<devicetree@vger.kernel.org>, Kees Cook <keescook@chromium.org>,
Jonas Karlman <jonas@kwiboo.se>, Mark Brown <broonie@kernel.org>,
Maxime Ripard <maxime@cerno.tech>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Liam Girdwood <lgirdwood@gmail.com>,
Robert Foss <robert.foss@linaro.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Rob Herring <robh+dt@kernel.org>, Daniel Vetter <daniel@ffwll.ch>,
Hans Verku il <hverkuil-cisco@xs4all.nl>,
Discussions about the Letux Kernel
<letux-kernel@openphoenux.org>
Subject: Re: [PATCH v5 2/7] drm/ingenic: Add support for JZ4780 and HDMI output
Date: Wed, 19 Jan 2022 21:04:22 +0100 [thread overview]
Message-ID: <4681844.iUxLBkU96p@jason> (raw)
In-Reply-To: <D0989ACA-F6DB-4E16-8D95-5ACBAD90AACD@goldelico.com>
On Wednesday, 19 January 2022 07:40:22 CET H. Nikolaus Schaller wrote:
> Hi Paul,
>
> > Am 18.01.2022 um 23:59 schrieb Paul Boddie <paul@boddie.org.uk>:
> >
> > On Tuesday, 18 January 2022 17:58:58 CET Paul Cercueil wrote:
> >>
> >> Why is this JZ_LCD_OSDC_ALPHAEN bit needed now? I remember it working
> >> fine last time I tried, and now I indeed get a black screen unless this
> >> bit is set. The PM doesn't make it obvious that the bit is required,
> >> but that wouldn't be surprising.
> >
> > It isn't actually needed. If the DMA descriptors are set up appropriately,
> > the OSD alpha bit seems to be set as a consequence. In my non-Linux
> > testing environment I don't even set any OSD registers explicitly, but
> > the OSD alpha and enable flags become set when the display is active.
>
> Is it set by DMA descriptors or by explicit code?
The descriptors will cause it to be set when the peripheral is enabled, as far
as I can tell.
> We did have an explicit setting of JZ_LCD_OSDC_ALPHAEN
>
> https://www.spinics.net/lists/devicetree/msg438447.html
>
> but that was postponed for further discussion. And now if we
> add it (from basic functionality) back, it is fine again.
It may be set in various versions of the Linux driver, but my observation was
that in a non-Linux environment where nothing else is setting anything in the
register concerned, initialising the descriptors seems to enable OSD and the
OSD alpha enable bit.
Yesterday, I did consider what might be done to avoid the alpha bit being set,
but I didn't immediately see anything in the descriptor fields that would
offer such an alternative. The bit in question seems to be a global alpha
enable setting, and so choosing per-pixel alpha would probably also result in
it being set, although I didn't fire up the CI20 to check.
Paul
next prev parent reply other threads:[~2022-01-19 20:04 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-05 12:29 [PATCH v5 0/7] MIPS: JZ4780 and CI20 HDMI H. Nikolaus Schaller
2021-10-05 12:29 ` [PATCH v5 1/7] drm/ingenic: Fix drm_init error path if IPU was registered H. Nikolaus Schaller
2021-10-05 12:29 ` [PATCH v5 2/7] drm/ingenic: Add support for JZ4780 and HDMI output H. Nikolaus Schaller
2021-10-05 20:22 ` Paul Cercueil
[not found] ` <7CEBB741-2218-40A7-9800-B3A154895274@goldelico.com>
2021-11-07 19:01 ` Paul Cercueil
2021-11-07 20:25 ` H. Nikolaus Schaller
2021-11-08 9:37 ` Paul Cercueil
2021-11-08 10:52 ` H. Nikolaus Schaller
2021-11-08 12:20 ` Paul Cercueil
2021-11-08 15:29 ` H. Nikolaus Schaller
2021-11-08 16:30 ` Paul Cercueil
2021-11-08 17:22 ` H. Nikolaus Schaller
2021-11-08 17:49 ` Paul Cercueil
2021-11-08 18:33 ` H. Nikolaus Schaller
2021-11-08 18:53 ` Paul Cercueil
2021-12-22 14:03 ` H. Nikolaus Schaller
2022-01-18 14:50 ` H. Nikolaus Schaller
2022-01-18 16:58 ` Paul Cercueil
2022-01-18 17:14 ` H. Nikolaus Schaller
[not found] ` <13356060.GkHXLIg068@jason>
2022-01-19 6:40 ` H. Nikolaus Schaller
2022-01-19 20:04 ` Paul Boddie [this message]
2021-10-05 12:29 ` [PATCH v5 3/7] dt-bindings: display: Add ingenic,jz4780-dw-hdmi DT Schema H. Nikolaus Schaller
2021-10-05 20:43 ` Paul Cercueil
2021-11-07 13:43 ` H. Nikolaus Schaller
2021-11-07 19:03 ` Paul Cercueil
2021-10-05 22:45 ` Rob Herring
2021-10-05 12:29 ` [PATCH v5 4/7] drm/ingenic: Add dw-hdmi driver for jz4780 H. Nikolaus Schaller
2021-10-05 12:29 ` [PATCH v5 5/7] MIPS: DTS: jz4780: Account for Synopsys HDMI driver and LCD controllers H. Nikolaus Schaller
2021-10-05 20:50 ` Paul Cercueil
2021-10-05 21:44 ` Paul Boddie
2021-10-05 21:52 ` Paul Cercueil
2021-11-07 13:45 ` H. Nikolaus Schaller
2021-11-07 19:05 ` Paul Cercueil
2021-11-09 20:19 ` H. Nikolaus Schaller
2021-11-09 20:36 ` Paul Cercueil
2021-11-09 20:42 ` H. Nikolaus Schaller
2021-11-09 21:14 ` [Letux-kernel] " H. Nikolaus Schaller
2021-10-05 12:29 ` [PATCH v5 6/7] MIPS: DTS: CI20: Add DT nodes for HDMI setup H. Nikolaus Schaller
2021-10-05 12:29 ` [PATCH v5 7/7] MIPS: defconfig: CI20: configure for DRM_DW_HDMI_JZ4780 H. Nikolaus Schaller
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