From: Pekka Paalanen <ppaalanen@gmail.com> To: Harry Wentland <harry.wentland@amd.com> Cc: Deepak.Sharma@amd.com, Krunoslav.Kovac@amd.com, mcasas@google.com, Shashank.Sharma@amd.com, dri-devel@lists.freedesktop.org, Shirish.S@amd.com, Sebastian Wick <sebastian@sebastianwick.net>, Uma Shankar <uma.shankar@intel.com>, hersenxs.wu@amd.com, amd-gfx@lists.freedesktop.org, laurentiu.palcu@oss.nxp.com, Bhawanpreet.Lakha@amd.com, Nicholas.Kazlauskas@amd.com, Vitaly.Prosyak@amd.com Subject: Re: [RFC PATCH 1/3] drm/color: Add RGB Color encodings Date: Mon, 17 May 2021 11:34:32 +0300 [thread overview] Message-ID: <20210517113432.11f95361@eldfell> (raw) In-Reply-To: <cac44e69-85cb-661b-4a5e-33fafee8ea3d@amd.com> [-- Attachment #1: Type: text/plain, Size: 1854 bytes --] On Fri, 14 May 2021 17:04:51 -0400 Harry Wentland <harry.wentland@amd.com> wrote: > On 2021-04-30 8:53 p.m., Sebastian Wick wrote: > > On 2021-04-26 20:56, Harry Wentland wrote: ... > >> Another reason I'm proposing to define the color space (and gamma) of > >> a plane is to make this explicit. Up until the color space and gamma > >> of a plane or framebuffer are not well defined, which leads to drivers > >> assuming the color space and gamma of a buffer (for blending and other > >> purposes) and might lead to sub-optimal outcomes. > > > > Blending only is "correct" with linear light so that property of the > > color space is important. However, why does the kernel have to be > > involved here? As long as user space knows that for correct blending the > > data must represent linear light and knows when in the pipeline blending > > happens it can make sure that the data at that point in the pipeline > > contains linear light. > > > > The only reason the kernel needs to be involved is to take full advantage > of the available HW without requiring KMS clients to be aware of > the difference in display HW. Can you explain in more tangible examples, why you think so, please? Is it because hardware does not fit the KMS UAPI model of the abstract pixel pipeline? Or is it because you have fixed-function hardware elements that you can only make use of when userspace uses an enum-based UAPI? I would totally agree that the driver does not want to be analysing LUT entries to decipher if it could use a fixed-function element or not. It would introduce uncertainty in the UAPI. So fixed-function elements would need their own properties, but I don't know if that is feasible as generic UAPI or if it should be driver-specific (and so left unused by generic userspace). 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: Harry Wentland <harry.wentland@amd.com> Cc: Deepak.Sharma@amd.com, aric.cyr@amd.com, Krunoslav.Kovac@amd.com, mcasas@google.com, Shashank.Sharma@amd.com, dri-devel@lists.freedesktop.org, Shirish.S@amd.com, "Sebastian Wick" <sebastian@sebastianwick.net>, "Uma Shankar" <uma.shankar@intel.com>, hersenxs.wu@amd.com, amd-gfx@lists.freedesktop.org, laurentiu.palcu@oss.nxp.com, Bhawanpreet.Lakha@amd.com, Nicholas.Kazlauskas@amd.com, "Ville Syrjälä" <ville.syrjala@linux.intel.com>, Vitaly.Prosyak@amd.com Subject: Re: [RFC PATCH 1/3] drm/color: Add RGB Color encodings Date: Mon, 17 May 2021 11:34:32 +0300 [thread overview] Message-ID: <20210517113432.11f95361@eldfell> (raw) In-Reply-To: <cac44e69-85cb-661b-4a5e-33fafee8ea3d@amd.com> [-- Attachment #1.1: Type: text/plain, Size: 1854 bytes --] On Fri, 14 May 2021 17:04:51 -0400 Harry Wentland <harry.wentland@amd.com> wrote: > On 2021-04-30 8:53 p.m., Sebastian Wick wrote: > > On 2021-04-26 20:56, Harry Wentland wrote: ... > >> Another reason I'm proposing to define the color space (and gamma) of > >> a plane is to make this explicit. Up until the color space and gamma > >> of a plane or framebuffer are not well defined, which leads to drivers > >> assuming the color space and gamma of a buffer (for blending and other > >> purposes) and might lead to sub-optimal outcomes. > > > > Blending only is "correct" with linear light so that property of the > > color space is important. However, why does the kernel have to be > > involved here? As long as user space knows that for correct blending the > > data must represent linear light and knows when in the pipeline blending > > happens it can make sure that the data at that point in the pipeline > > contains linear light. > > > > The only reason the kernel needs to be involved is to take full advantage > of the available HW without requiring KMS clients to be aware of > the difference in display HW. Can you explain in more tangible examples, why you think so, please? Is it because hardware does not fit the KMS UAPI model of the abstract pixel pipeline? Or is it because you have fixed-function hardware elements that you can only make use of when userspace uses an enum-based UAPI? I would totally agree that the driver does not want to be analysing LUT entries to decipher if it could use a fixed-function element or not. It would introduce uncertainty in the UAPI. So fixed-function elements would need their own properties, but I don't know if that is feasible as generic UAPI or if it should be driver-specific (and so left unused by generic userspace). Thanks, pq [-- Attachment #1.2: OpenPGP digital signature --] [-- Type: application/pgp-signature, Size: 833 bytes --] [-- Attachment #2: Type: text/plain, Size: 154 bytes --] _______________________________________________ amd-gfx mailing list amd-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/amd-gfx
next prev parent reply other threads:[~2021-05-17 8:34 UTC|newest] Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-04-26 17:38 [RFC PATCH 0/3] A drm_plane API to support HDR planes Harry Wentland 2021-04-26 17:38 ` Harry Wentland 2021-04-26 17:38 ` [RFC PATCH 1/3] drm/color: Add RGB Color encodings Harry Wentland 2021-04-26 17:38 ` Harry Wentland 2021-04-26 18:07 ` Ville Syrjälä 2021-04-26 18:07 ` Ville Syrjälä 2021-04-26 18:56 ` Harry Wentland 2021-04-26 18:56 ` Harry Wentland 2021-04-26 19:08 ` Ville Syrjälä 2021-04-26 19:08 ` Ville Syrjälä 2021-04-30 9:04 ` Pekka Paalanen 2021-04-30 9:04 ` Pekka Paalanen 2021-05-01 0:53 ` Sebastian Wick 2021-05-01 0:53 ` Sebastian Wick 2021-05-14 21:04 ` Harry Wentland 2021-05-14 21:04 ` Harry Wentland 2021-05-17 8:34 ` Pekka Paalanen [this message] 2021-05-17 8:34 ` Pekka Paalanen 2021-05-18 14:32 ` Harry Wentland 2021-05-18 14:32 ` Harry Wentland 2021-05-19 7:56 ` Pekka Paalanen 2021-05-19 7:56 ` Pekka Paalanen 2021-04-26 17:38 ` [RFC PATCH 2/3] drm/color: Add Color transfer functions for HDR/SDR Harry Wentland 2021-04-26 17:38 ` Harry Wentland 2021-04-26 19:03 ` kernel test robot 2021-04-26 20:27 ` kernel test robot 2021-04-26 20:27 ` [RFC PATCH] drm/color: drm_get_color_transfer_function_name() can be static kernel test robot 2021-04-26 21:29 ` [RFC PATCH 2/3] drm/color: Add Color transfer functions for HDR/SDR kernel test robot 2021-04-26 22:00 ` kernel test robot 2021-04-26 17:38 ` [RFC PATCH 3/3] drm/color: Add sdr boost property Harry Wentland 2021-04-26 17:38 ` Harry Wentland 2021-04-26 20:38 ` kernel test robot 2021-04-26 21:45 ` kernel test robot 2021-04-26 21:45 ` [RFC PATCH] drm/color: drm_plane_create_sdr_white_level_property() can be static kernel test robot 2021-04-27 9:09 ` [RFC PATCH 0/3] A drm_plane API to support HDR planes Daniel Vetter 2021-04-27 9:09 ` Daniel Vetter 2021-04-27 14:50 ` Pekka Paalanen 2021-04-27 14:50 ` Pekka Paalanen 2021-04-28 7:54 ` Shashank Sharma 2021-04-28 7:54 ` Shashank Sharma 2021-04-30 9:43 ` Pekka Paalanen 2021-04-30 9:43 ` Pekka Paalanen 2021-04-30 10:39 ` Shashank Sharma 2021-04-30 10:39 ` Shashank Sharma 2021-05-14 21:01 ` Harry Wentland 2021-05-14 21:01 ` Harry Wentland 2021-05-14 21:05 ` Harry Wentland 2021-05-14 21:05 ` Harry Wentland 2021-05-17 8:57 ` Pekka Paalanen 2021-05-17 8:57 ` Pekka Paalanen 2021-05-17 16:48 ` Sebastian Wick 2021-05-17 16:48 ` Sebastian Wick 2021-05-17 19:39 ` Vitaly Prosyak 2021-05-17 19:39 ` Vitaly Prosyak 2021-05-18 7:56 ` Pekka Paalanen 2021-05-18 7:56 ` Pekka Paalanen 2021-05-18 14:19 ` Harry Wentland 2021-05-18 14:19 ` Harry Wentland 2021-05-18 23:00 ` Sebastian Wick 2021-05-18 23:00 ` Sebastian Wick 2021-05-19 8:53 ` Pekka Paalanen 2021-05-19 8:53 ` Pekka Paalanen 2021-05-19 10:02 ` Pekka Paalanen 2021-05-19 10:02 ` Pekka Paalanen
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