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From: Linus Walleij <linus.walleij@linaro.org>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: "Alexandre Belloni" <alexandre.belloni@bootlin.com>,
	"Neil Armstrong" <narmstrong@baylibre.com>,
	"Maxime Ripard" <maxime.ripard@bootlin.com>,
	"Guido Günther" <agx@sigxcpu.org>,
	"open list:DRM PANEL DRIVERS" <dri-devel@lists.freedesktop.org>,
	"Philippe Cornu" <philippe.cornu@st.com>,
	"Paul Cercueil" <paul@crapouillou.net>,
	"Thierry Reding" <thierry.reding@gmail.com>,
	"Laurent Pinchart" <laurent.pinchart@ideasonboard.com>,
	"Yannick Fertre" <yannick.fertre@st.com>,
	"Stefan Mavrodiev" <stefan@olimex.com>,
	"Tomi Valkeinen" <tomi.valkeinen@ti.com>,
	"Ludovic Desroches" <ludovic.desroches@microchip.com>,
	"Jagan Teki" <jagan@amarulasolutions.com>,
	"Robert Chiras" <robert.chiras@nxp.com>,
	"Jonas Karlman" <jonas@kwiboo.se>, "Jyri Sarha" <jsarha@ti.com>,
	"Sean Paul" <sean@poorly.run>,
	"Jernej Skrabec" <jernej.skrabec@siol.net>,
	"Purism Kernel Team" <kernel@puri.sm>,
	"Boris Brezillon" <bbrezillon@kernel.o>
Subject: Re: DRM_MODE_CONNECTOR_PANEL? [Was: drm/panel: Add and fill drm_panel type field]
Date: Fri, 27 Sep 2019 14:37:42 +0200	[thread overview]
Message-ID: <CACRpkdYk8S271X7pV_Vxe7BhL_mScV69Xbet2xyOqF0fFsRdcg@mail.gmail.com> (raw)
In-Reply-To: <20190824095421.GC30584@ravnborg.org>

Just a drive-by comment:

On Sat, Aug 24, 2019 at 11:54 AM Sam Ravnborg <sam@ravnborg.org> wrote:

> We will also start to see new drivers where there will be support
> for more than one type of connector interface.
>
> Like for example ili9322:
>  - 8-bit serial RGB interface
>  - 24-bit parallel RGB interface
>  - 8-bit ITU-R BT.601 interface
>  - 8-bit ITU-R BT.656 interface

I just found all these weird references when making the ILI9322 driver
and trying to really understand what was going on in the hardware.
I have this special nack (shared with many kernel developers) that I
need to know what is going on.

I think what is actually the case is that a *lot* of panels that we
support (especially the so-called "simple" panels) are actually complex,
like the ILI9322, just that many of them are undocumented, set up by
ROM or bootloaders, their SPI/I2C lines forgotten about and the
sum result added as a "simple panel" in panel-simple.c.

This is fine I guess to get some basic support up and going,
but all of a sudden someone will use that bridge/panel with
some other input from the list above and ooops wrongly modeled,
the DT compatible string makes no sense etc.

Also the ILI9322 can actually set up gamma correction which is
very nice for professional applications. I haven't seen any way for
DRM to do gamma correction properly or any framework for it
to adjust and propagate gamma to/from userspace (seems like
another enormous task), but I am pretty sure it will be there one
of these days so I put in some comments and placeholders.

Yours,
Linus Walleij
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

  parent reply	other threads:[~2019-09-27 12:37 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-23 19:32 [PATCH v2 0/4] drm/panel: Extend panels to report their types Laurent Pinchart
2019-08-23 19:32 ` [PATCH v2 1/4] drm/panel: Add missing drm_panel_init() in panel drivers Laurent Pinchart
2019-08-24  8:48   ` Sam Ravnborg
2019-08-23 19:32 ` [PATCH v2 2/4] drm/panel: Initialise panel dev and funcs through drm_panel_init() Laurent Pinchart
2019-08-24  8:50   ` Sam Ravnborg
2019-08-23 19:32 ` [PATCH v2 3/4] drm/panel: Add and fill drm_panel type field Laurent Pinchart
2019-08-24  9:54   ` DRM_MODE_CONNECTOR_PANEL? [Was: drm/panel: Add and fill drm_panel type field] Sam Ravnborg
2019-08-24 14:02     ` Laurent Pinchart
2019-09-04 13:13       ` Laurent Pinchart
2019-09-27 12:37     ` Linus Walleij [this message]
2019-09-27 12:44       ` Daniel Stone
2019-09-27 14:28         ` Tomi Valkeinen
2019-10-08  8:42           ` Daniel Vetter
2019-08-26  7:46   ` [PATCH v2 3/4] drm/panel: Add and fill drm_panel type field Boris Brezillon
2019-08-23 19:32 ` [PATCH v2 4/4] drm/bridge: panel: Infer connector type from panel by default Laurent Pinchart
2019-08-26  7:47   ` Boris Brezillon

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