From: Maxime Ripard <maxime.ripard@bootlin.com>
To: Hans Verkuil <hverkuil@xs4all.nl>
Cc: Nicolas Dufresne <nicolas@ndufresne.ca>,
Daniel Vetter <daniel.vetter@intel.com>,
David Airlie <airlied@linux.ie>,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Sean Paul <seanpaul@chromium.org>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Sakari Ailus <sakari.ailus@linux.intel.com>,
Hans Verkuil <hans.verkuil@cisco.com>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
Paul Kocialkowski <paul.kocialkowski@bootlin.com>,
dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
linux-media@vger.kernel.org
Subject: Re: [RFC PATCH 18/20] lib: image-formats: Add v4l2 formats support
Date: Thu, 11 Apr 2019 17:55:40 +0200 [thread overview]
Message-ID: <20190411155540.poquzzx2apa5ahgb@flea> (raw)
In-Reply-To: <5385672c-cfee-7bc4-9c2e-e4d8d964b748@xs4all.nl>
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Hi,
On Thu, Apr 11, 2019 at 09:38:06AM +0200, Hans Verkuil wrote:
> >> @@ -149,6 +155,7 @@ static const struct image_format_info formats[] = {
> >> .has_alpha = true,
> >> }, {
> >> .drm_fmt = DRM_FORMAT_RGB565,
> >> + .v4l2_fmt = V4L2_PIX_FMT_RGB565,
> >
> > -> V4L2_PIX_FMT_RGB565X
> >
> > Was added later, as what you expect is not compatible.
>
> All these 16-bit V4L2 pixelformats are ancient, but they are (to my knowledge)
> correct w.r.t. the documented layout of the bits in memory. I.e., that's what
> the hardware will give you.
>
> I think if there is no equivalence between the drm and v4l2 fourcc's, then
> you need two entries in this table, one for drm (v4l2_fmt == 0), one for v4l2
> (drm_fmt == 0).
Yeah, that was my plan. I'd definitely expect some formats in V4L2
while not supported by DRM, or the other way around.
> >> @@ -473,6 +496,7 @@ static const struct image_format_info formats[] = {
> >> .is_yuv = true,
> >> }, {
> >> .drm_fmt = DRM_FORMAT_NV24,
> >> + .v4l2_fmt = V4L2_PIX_FMT_NV24,
> >
> > For extra fun, the M variant has not been added yet.
>
> Note that it has been the practice in V4L2 to avoid adding pixelformats unless
> they are in use by a V4L2 driver. So that's why some combinations do not exist.
>
> If we are creating a common library then I think we should change that rule
> to: "unless they are in use by a DRM or V4L2 driver". And when new formats are
> added, and they exists already for DRM or V4L2, then we should use the same
> fourcc for the other subsystem.
>
> I.e. if pixelformat V4L2_PIX_FMT_FOO was already defined, then add a:
>
> #define DRM_FORMAT_FOO V4L2_PIX_FMT_FOO
>
> rather than creating a new fourcc.
That makes sense
> We could even start looking at redoing the whole scheme in a unified way, but
> that's something for the (far) future.
Yeah, my secret plan is to have eventually a single fourcc (or even
#define) for both DRM and v4l2 for any new format. But don't tell
anyone :)
> This is already a big step forward.
Great, I'll respin this then.
Maxime
--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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next prev parent reply other threads:[~2019-04-11 15:55 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-19 21:57 [RFC PATCH 00/20] drm: Split out the formats API and move it to a common place Maxime Ripard
2019-03-19 21:57 ` [RFC PATCH 01/20] drm: Remove users of drm_format_num_planes Maxime Ripard
2019-03-20 14:16 ` Paul Kocialkowski
2019-04-02 9:43 ` Emil Velikov
2019-04-02 14:51 ` Maxime Ripard
2019-04-04 16:24 ` Emil Velikov
2019-03-19 21:57 ` [RFC PATCH 02/20] drm: Remove users of drm_format_(horz|vert)_chroma_subsampling Maxime Ripard
2019-03-20 14:19 ` Paul Kocialkowski
2019-03-19 21:57 ` [RFC PATCH 03/20] drm/fourcc: Pass the format_info pointer to drm_format_plane_cpp Maxime Ripard
2019-03-20 14:24 ` Paul Kocialkowski
2019-03-21 10:13 ` Maxime Ripard
2019-03-19 21:57 ` [RFC PATCH 04/20] drm/fourcc: Pass the format_info pointer to drm_format_plane_width/height Maxime Ripard
2019-03-20 14:26 ` Paul Kocialkowski
2019-03-19 21:57 ` [RFC PATCH 05/20] drm: Replace instances of drm_format_info by drm_get_format_info Maxime Ripard
2019-03-20 14:27 ` Paul Kocialkowski
2019-03-19 21:57 ` [RFC PATCH 06/20] lib: Add video format information library Maxime Ripard
2019-03-20 13:39 ` Boris Brezillon
2019-03-21 8:20 ` Maxime Ripard
2019-03-21 8:40 ` Boris Brezillon
2019-03-19 21:57 ` [RFC PATCH 07/20] drm/fb: Move from drm_format_info to image_format_info Maxime Ripard
2019-03-19 21:57 ` [RFC PATCH 08/20] drm/malidp: Convert to generic image format library Maxime Ripard
2019-03-19 21:57 ` [RFC PATCH 09/20] drm/client: " Maxime Ripard
2019-03-19 21:57 ` [RFC PATCH 10/20] drm/exynos: " Maxime Ripard
2019-03-19 21:57 ` [RFC PATCH 11/20] drm/i915: " Maxime Ripard
2019-03-19 21:57 ` [RFC PATCH 12/20] drm/ipuv3: " Maxime Ripard
2019-03-19 21:57 ` [RFC PATCH 13/20] drm/msm: " Maxime Ripard
2019-03-19 21:57 ` [RFC PATCH 14/20] drm/omap: " Maxime Ripard
2019-03-19 21:57 ` [RFC PATCH 15/20] drm/rockchip: " Maxime Ripard
2019-03-19 21:57 ` [RFC PATCH 16/20] drm/tegra: " Maxime Ripard
2019-03-19 21:57 ` [RFC PATCH 17/20] drm/fourcc: Remove old DRM format API Maxime Ripard
2019-03-19 21:57 ` [RFC PATCH 18/20] lib: image-formats: Add v4l2 formats support Maxime Ripard
2019-03-19 23:29 ` Nicolas Dufresne
2019-03-20 14:27 ` Ville Syrjälä
2019-03-20 15:51 ` Nicolas Dufresne
2019-03-20 16:09 ` Ville Syrjälä
2019-03-20 16:30 ` Nicolas Dufresne
2019-03-20 16:41 ` Ville Syrjälä
2019-03-20 18:27 ` Nicolas Dufresne
2019-03-20 18:39 ` Ville Syrjälä
2019-03-21 16:04 ` Paul Kocialkowski
2019-03-21 16:35 ` Ville Syrjälä
2019-03-21 19:14 ` Nicolas Dufresne
2019-03-21 21:44 ` Ville Syrjälä
2019-03-22 18:24 ` Nicolas Dufresne
2019-03-22 18:44 ` Ville Syrjälä
2019-03-22 19:25 ` Nicolas Dufresne
2019-03-22 14:42 ` Ville Syrjälä
2019-03-22 18:11 ` Nicolas Dufresne
2019-03-20 18:15 ` Brian Starkey
2019-03-21 15:47 ` Maxime Ripard
2019-03-22 19:55 ` Nicolas Dufresne
2019-04-01 14:44 ` Maxime Ripard
2019-04-11 7:24 ` Hans Verkuil
2019-04-11 7:38 ` Hans Verkuil
2019-04-11 15:55 ` Maxime Ripard [this message]
2019-04-11 7:12 ` Hans Verkuil
2019-04-11 7:15 ` Hans Verkuil
2019-03-19 21:57 ` [RFC PATCH 19/20] lib: image-formats: Add more functions Maxime Ripard
2019-03-19 21:57 ` [RFC PATCH 20/20] media: sun6i: Convert to the image format API Maxime Ripard
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