From: "Michel Dänzer" <michel.daenzer@mailbox.org>
To: Gerd Hoffmann <kraxel@redhat.com>,
Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "Linux Fbdev development list" <linux-fbdev@vger.kernel.org>,
"Thomas Zimmermann" <tzimmermann@suse.de>,
"David Airlie" <airlied@linux.ie>,
Linux/m68k <linux-m68k@vger.kernel.org>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
"Noralf Trønnes" <noralf@tronnes.org>,
"DRI Development" <dri-devel@lists.freedesktop.org>
Subject: Re: [PATCH 1/3] drm/fourcc: Add missing big-endian XRGB1555 and RGB565 formats
Date: Tue, 12 Jul 2022 11:09:25 +0200 [thread overview]
Message-ID: <69a6aac7-0d48-7361-9750-8f242d374d60@mailbox.org> (raw)
In-Reply-To: <20220712090305.44jq3olwhwypisoc@sirius.home.kraxel.org>
On 2022-07-12 11:03, Gerd Hoffmann wrote:
>>> As described above DRM_FORMAT_HOST_RGB565 means bigendian on bigendian
>>> hosts and little endian on little endian hosts. Which is not correct
>>> when your hardware does big endian no matter what.
>>
>> But (a) drm_driver_legacy_fb_format() uses DRM_FORMAT_HOST_RGB565
>> if quirk_addfb_prefer_host_byte_order is set,
>
> Ah, right. Missed that in 'git grep' output. Given that traditional
> fbdev behavior is to expect native byte order using
> DRM_FORMAT_HOST_RGB565 there makes sense indeed.
>
> Scratch my comment about it being unused then ;)
DRM_FORMAT_RGB565 | DRM_FORMAT_BIG_ENDIAN is still what the driver should use conceptually, and should match DRM_FORMAT_HOST_RGB565 in drm_driver_legacy_fb_format on a big endian host (which is presumably always the case for the atari driver).
--
Earthling Michel Dänzer | https://redhat.com
Libre software enthusiast | Mesa and Xwayland developer
next prev parent reply other threads:[~2022-07-12 9:09 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-08 18:21 [PATCH 0/3] drm: Endianness fixes Geert Uytterhoeven
2022-07-08 18:21 ` [PATCH 1/3] drm/fourcc: Add missing big-endian XRGB1555 and RGB565 formats Geert Uytterhoeven
2022-07-11 15:22 ` Michel Dänzer
2022-07-11 15:30 ` Geert Uytterhoeven
2022-07-11 16:28 ` Michel Dänzer
2022-07-12 7:47 ` Gerd Hoffmann
2022-07-12 8:01 ` Geert Uytterhoeven
2022-07-12 8:39 ` Gerd Hoffmann
2022-07-12 8:43 ` Geert Uytterhoeven
2022-07-12 9:03 ` Gerd Hoffmann
2022-07-12 9:09 ` Michel Dänzer [this message]
2022-07-12 9:10 ` Geert Uytterhoeven
2022-07-12 8:31 ` Gerd Hoffmann
2022-07-08 18:21 ` [PATCH 2/3] drm/format-helper: Fix endianness in drm_fb_*_to_*() conversion helpers Geert Uytterhoeven
2022-07-08 18:21 ` [PATCH 3/3] drm/gud: Fix endianness in gud_xrgb8888_to_color() helper Geert Uytterhoeven
2022-07-19 14:39 ` Noralf Trønnes
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