From: Daniel Vetter <daniel@ffwll.ch>
To: Adam Jackson <ajax@redhat.com>
Cc: Fabian Vogt <fabian@ritter-vogt.de>,
Daniel Tang <dt.tangr@gmail.com>,
Linus Walleij <linus.walleij@linaro.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 1/3] RFT: drm/pl111: Support grayscale
Date: Tue, 23 Jul 2019 23:06:58 +0200 [thread overview]
Message-ID: <CAKMK7uHVudGdTzQS3Q6qVTZtDU-UsSQ2K04M9VvZHxzXo0DHOw@mail.gmail.com> (raw)
In-Reply-To: <9c9b77b3b76e7a7e87c7c3d9076a8339362157bd.camel@redhat.com>
On Tue, Jul 23, 2019 at 7:25 PM Adam Jackson <ajax@redhat.com> wrote:
>
> On Tue, 2019-07-23 at 15:37 +0200, Linus Walleij wrote:
> > Migrating the TI nspire calculators to use the PL111 driver for
> > framebuffer requires grayscale support for the elder panel
> > which uses 8bit grayscale only.
> >
> > DRM does not support 8bit grayscale framebuffers in memory,
> > but by defining the bus format to be MEDIA_BUS_FMT_Y8_1X8 we
> > can get the hardware to turn on a grayscaling feature and
> > convert the RGB framebuffer to grayscale for us.
>
> What's wrong with DRM_FORMAT_R8? Yes the hardware is not really
> "redscale", but it's still a single color channel and there's not
> really any ambiguity.
Yeah, I think with a comment or an aliasing #define to _Y8 (or both)
this is good to go.
You probably still want to expose the rgb format since too much
userspace just assumes that xrgb8888 works. Same reason why the
tinydrm drivers do the sw conversion.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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next prev parent reply other threads:[~2019-07-23 21:07 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-23 13:37 [PATCH 0/3] RFT: PL111 DRM conversion of nspire Linus Walleij
2019-07-23 13:37 ` [PATCH 1/3] RFT: drm/pl111: Support grayscale Linus Walleij
2019-07-23 15:19 ` Fabian Vogt
2019-07-24 12:33 ` Linus Walleij
2019-07-25 19:26 ` Fabian Vogt
2019-08-03 9:51 ` Linus Walleij
2019-08-04 20:13 ` Fabian Vogt
2019-07-23 16:22 ` [1/3] " David Lechner
2019-07-23 17:25 ` [PATCH 1/3] " Adam Jackson
2019-07-23 21:06 ` Daniel Vetter [this message]
2019-07-24 12:52 ` Linus Walleij
2019-07-24 14:06 ` Daniel Vetter
2019-07-23 13:37 ` [PATCH 2/3] RTF: drm/panel: simple: Add TI nspire panels Linus Walleij
2019-07-23 17:54 ` Sam Ravnborg
2019-07-24 13:58 ` Linus Walleij
2019-07-24 18:53 ` Sam Ravnborg
2019-07-23 13:37 ` [PATCH 3/3] RFT: ARM: nspire: Move CLCD set-up to device tree Linus Walleij
2019-07-23 18:10 ` [PATCH 0/3] RFT: PL111 DRM conversion of nspire Sam Ravnborg
2019-07-24 12:28 ` Linus Walleij
2019-07-24 12:47 ` Pawel Moll
2019-07-24 12:53 ` Linus Walleij
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