From: Pekka Paalanen <ppaalanen@gmail.com> To: Hector Martin <marcan@marcan.st> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>, Maxime Ripard <mripard@kernel.org>, Thomas Zimmermann <tzimmermann@suse.de>, David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>, dri-devel@lists.freedesktop.org, Alyssa Rosenzweig <alyssa@rosenzweig.io>, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/3] drm/format-helper: Add drm_fb_xrgb8888_to_xrgb2101010_dstclip() Date: Mon, 22 Nov 2021 12:39:38 +0200 [thread overview] Message-ID: <20211122123938.47fcbef0@eldfell> (raw) In-Reply-To: <7e1356b9-3122-e169-193e-37547a50499a@marcan.st> [-- Attachment #1: Type: text/plain, Size: 1833 bytes --] On Mon, 22 Nov 2021 19:05:16 +0900 Hector Martin <marcan@marcan.st> wrote: > On 22/11/2021 18.52, Pekka Paalanen wrote: > > On Wed, 17 Nov 2021 23:58:28 +0900 > > Hector Martin <marcan@marcan.st> wrote: > > > >> Add XRGB8888 emulation support for devices that can only do XRGB2101010. > >> > >> This is chiefly useful for simpledrm on Apple devices where the > >> bootloader-provided framebuffer is 10-bit, which already works fine with > >> simplefb. This is required to make simpledrm support this too. > >> > >> Signed-off-by: Hector Martin <marcan@marcan.st> > >> --- > >> drivers/gpu/drm/drm_format_helper.c | 64 +++++++++++++++++++++++++++++ > >> include/drm/drm_format_helper.h | 4 ++ > >> 2 files changed, 68 insertions(+) > > > > Hi Hector, > > > > I'm curious, since the bootloader seems to always set up a 10-bit mode, > > is there a reason for it that you can guess? Is the monitor in WCG or > > even HDR mode? > > My guess is that Apple prefer to use 10-bit framebuffers for seamless > handover with their graphics stack, which presumably uses 10-bit > framebuffers these days. It seems to be unconditional; I've never seen > anything but 10 bits across all Apple devices, both with the internal > panels on laptops and with bog standard external displays on the Mac > Mini via HDMI. HDR is not necessary, even very dumb capture cards and > old screens get a 10-bit framebufer in memory. That makes perfect sense, thanks! Switching between sRGB and WCG or HDR mode is not a modeset, it's just HDMI/DP/whatever metadata/infoframe. > The only time I see an 8-bit framebuffer is with *no* monitor connected > on the Mini, in which case you get an 8-bit 640x1136 dummy framebuffer > (that's the iPhone 5 screen resolution... :-) ) > Thanks, pq [-- Attachment #2: OpenPGP digital signature --] [-- Type: application/pgp-signature, Size: 833 bytes --]
WARNING: multiple messages have this Message-ID (diff)
From: Pekka Paalanen <ppaalanen@gmail.com> To: Hector Martin <marcan@marcan.st> Cc: Thomas Zimmermann <tzimmermann@suse.de>, David Airlie <airlied@linux.ie>, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Alyssa Rosenzweig <alyssa@rosenzweig.io> Subject: Re: [PATCH 2/3] drm/format-helper: Add drm_fb_xrgb8888_to_xrgb2101010_dstclip() Date: Mon, 22 Nov 2021 12:39:38 +0200 [thread overview] Message-ID: <20211122123938.47fcbef0@eldfell> (raw) In-Reply-To: <7e1356b9-3122-e169-193e-37547a50499a@marcan.st> [-- Attachment #1: Type: text/plain, Size: 1833 bytes --] On Mon, 22 Nov 2021 19:05:16 +0900 Hector Martin <marcan@marcan.st> wrote: > On 22/11/2021 18.52, Pekka Paalanen wrote: > > On Wed, 17 Nov 2021 23:58:28 +0900 > > Hector Martin <marcan@marcan.st> wrote: > > > >> Add XRGB8888 emulation support for devices that can only do XRGB2101010. > >> > >> This is chiefly useful for simpledrm on Apple devices where the > >> bootloader-provided framebuffer is 10-bit, which already works fine with > >> simplefb. This is required to make simpledrm support this too. > >> > >> Signed-off-by: Hector Martin <marcan@marcan.st> > >> --- > >> drivers/gpu/drm/drm_format_helper.c | 64 +++++++++++++++++++++++++++++ > >> include/drm/drm_format_helper.h | 4 ++ > >> 2 files changed, 68 insertions(+) > > > > Hi Hector, > > > > I'm curious, since the bootloader seems to always set up a 10-bit mode, > > is there a reason for it that you can guess? Is the monitor in WCG or > > even HDR mode? > > My guess is that Apple prefer to use 10-bit framebuffers for seamless > handover with their graphics stack, which presumably uses 10-bit > framebuffers these days. It seems to be unconditional; I've never seen > anything but 10 bits across all Apple devices, both with the internal > panels on laptops and with bog standard external displays on the Mac > Mini via HDMI. HDR is not necessary, even very dumb capture cards and > old screens get a 10-bit framebufer in memory. That makes perfect sense, thanks! Switching between sRGB and WCG or HDR mode is not a modeset, it's just HDMI/DP/whatever metadata/infoframe. > The only time I see an 8-bit framebuffer is with *no* monitor connected > on the Mini, in which case you get an 8-bit 640x1136 dummy framebuffer > (that's the iPhone 5 screen resolution... :-) ) > Thanks, pq [-- Attachment #2: OpenPGP digital signature --] [-- Type: application/pgp-signature, Size: 833 bytes --]
next prev parent reply other threads:[~2021-11-22 10:40 UTC|newest] Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-11-17 14:58 [PATCH 0/3] drm/simpledrm: Apple M1 / DT platform support fixes Hector Martin 2021-11-17 14:58 ` Hector Martin 2021-11-17 14:58 ` [PATCH 1/3] drm/simpledrm: Bind to OF framebuffers in /chosen Hector Martin 2021-11-17 14:58 ` Hector Martin 2021-11-18 9:19 ` Thomas Zimmermann 2021-11-18 9:19 ` Thomas Zimmermann 2021-11-20 3:23 ` Hector Martin 2021-11-20 3:23 ` Hector Martin 2021-11-29 11:26 ` Thomas Zimmermann 2021-11-29 11:26 ` Thomas Zimmermann 2021-11-29 19:29 ` Rob Herring 2021-11-29 19:29 ` Rob Herring 2021-11-30 6:44 ` Javier Martinez Canillas 2021-11-30 6:44 ` Javier Martinez Canillas 2021-11-30 8:31 ` Thomas Zimmermann 2021-11-30 8:31 ` Thomas Zimmermann 2021-11-30 9:31 ` Javier Martinez Canillas 2021-11-30 9:31 ` Javier Martinez Canillas 2021-11-30 18:25 ` Rob Herring 2021-11-30 18:25 ` Rob Herring 2021-11-19 1:21 ` kernel test robot 2021-11-19 1:21 ` kernel test robot 2021-11-17 14:58 ` [PATCH 2/3] drm/format-helper: Add drm_fb_xrgb8888_to_xrgb2101010_dstclip() Hector Martin 2021-11-17 14:58 ` Hector Martin 2021-11-18 9:16 ` Thomas Zimmermann 2021-11-18 9:16 ` Thomas Zimmermann 2021-11-22 9:52 ` Pekka Paalanen 2021-11-22 9:52 ` Pekka Paalanen 2021-11-22 10:05 ` Hector Martin 2021-11-22 10:05 ` Hector Martin 2021-11-22 10:39 ` Pekka Paalanen [this message] 2021-11-22 10:39 ` Pekka Paalanen 2021-11-17 14:58 ` [PATCH 3/3] drm/simpledrm: Enable XRGB2101010 format Hector Martin 2021-11-17 14:58 ` Hector Martin 2021-11-18 9:16 ` Thomas Zimmermann 2021-11-18 9:16 ` Thomas Zimmermann
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