From: Daniel Vetter <daniel.vetter@ffwll.ch>
To: DRI Development <dri-devel@lists.freedesktop.org>,
Lyude <lyude@redhat.com>
Cc: Pekka Paalanen <pekka.paalanen@collabora.com>,
David Airlie <airlied@linux.ie>,
Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
Maxime Ripard <maxime@cerno.tech>,
Thomas Zimmermann <tzimmermann@suse.de>,
Daniel Vetter <daniel.vetter@intel.com>
Subject: Re: [PATCH 8/8] drm/modifiers: Enforce consistency between the cap an IN_FORMATS
Date: Wed, 5 May 2021 21:24:19 +0200 [thread overview]
Message-ID: <CAKMK7uHnkxaqKMU+K9ioj0YFjqa+sc5NH6Jy6fW1eeViSZ4=vA@mail.gmail.com> (raw)
In-Reply-To: <20210427092018.832258-8-daniel.vetter@ffwll.ch>
On Tue, Apr 27, 2021 at 11:20 AM Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
>
> It's very confusing for userspace to have to deal with inconsistencies
> here, and some drivers screwed this up a bit. Most just ommitted the
> format list when they meant to say that only linear modifier is
> allowed, but some also meant that only implied modifiers are
> acceptable (because actually none of the planes registered supported
> modifiers).
>
> Now that this is all done consistently across all drivers, document
> the rules and enforce it in the drm core.
>
> v2:
> - Make the capability a link (Simon)
> - Note that all is lost before 5.1.
>
> Acked-by: Maxime Ripard <maxime@cerno.tech>
> Cc: Simon Ser <contact@emersion.fr>
> Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
> Cc: Pekka Paalanen <pekka.paalanen@collabora.com>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Maxime Ripard <mripard@kernel.org>
> Cc: Thomas Zimmermann <tzimmermann@suse.de>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
Lyude's irc review:
<Lyude> btw danvet (sorry I didn't reply in-line, for some reason I
can't actually seem to find the emails for your allow_fb_modifiers
series in my email client), I just looked over your allow_fb_modifiers
series and everything looks fine with one comment:
https://lore.kernel.org/dri-devel/20210427092018.832258-8-daniel.vetter@ffwll.ch/
we should probably use drm_WARN_ON() here instead
<Lyude> with that fixed: Reviewed-by: Lyude Paul <lyude@redhat.com>
I'll merge the driver patches and respin this one afterwards.
-Daniel
> ---
> drivers/gpu/drm/drm_plane.c | 18 +++++++++++++++++-
> include/drm/drm_mode_config.h | 2 ++
> 2 files changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
> index 0dd43882fe7c..20c7a1665414 100644
> --- a/drivers/gpu/drm/drm_plane.c
> +++ b/drivers/gpu/drm/drm_plane.c
> @@ -128,6 +128,13 @@
> * pairs supported by this plane. The blob is a struct
> * drm_format_modifier_blob. Without this property the plane doesn't
> * support buffers with modifiers. Userspace cannot change this property.
> + *
> + * Note that userspace can check the &DRM_CAP_ADDFB2_MODIFIERS driver
> + * capability for general modifier support. If this flag is set then every
> + * plane will have the IN_FORMATS property, even when it only supports
> + * DRM_FORMAT_MOD_LINEAR. Before linux kernel release v5.1 there have been
> + * various bugs in this area with inconsistencies between the capability
> + * flag and per-plane properties.
> */
>
> static unsigned int drm_num_planes(struct drm_device *dev)
> @@ -277,8 +284,14 @@ static int __drm_universal_plane_init(struct drm_device *dev,
> format_modifier_count++;
> }
>
> - if (format_modifier_count)
> + /* autoset the cap and check for consistency across all planes */
> + if (format_modifier_count) {
> + WARN_ON(!config->allow_fb_modifiers &&
> + !list_empty(&config->plane_list));
> config->allow_fb_modifiers = true;
> + } else {
> + WARN_ON(config->allow_fb_modifiers);
> + }
>
> plane->modifier_count = format_modifier_count;
> plane->modifiers = kmalloc_array(format_modifier_count,
> @@ -360,6 +373,9 @@ static int __drm_universal_plane_init(struct drm_device *dev,
> * drm_universal_plane_init() to let the DRM managed resource infrastructure
> * take care of cleanup and deallocation.
> *
> + * Drivers supporting modifiers must set @format_modifiers on all their planes,
> + * even those that only support DRM_FORMAT_MOD_LINEAR.
> + *
> * Returns:
> * Zero on success, error code on failure.
> */
> diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
> index ab424ddd7665..1ddf7783fdf7 100644
> --- a/include/drm/drm_mode_config.h
> +++ b/include/drm/drm_mode_config.h
> @@ -909,6 +909,8 @@ struct drm_mode_config {
> * @allow_fb_modifiers:
> *
> * Whether the driver supports fb modifiers in the ADDFB2.1 ioctl call.
> + * Note that drivers should not set this directly, it is automatically
> + * set in drm_universal_plane_init().
> *
> * IMPORTANT:
> *
> --
> 2.31.0
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
next prev parent reply other threads:[~2021-05-05 19:24 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-27 9:20 [PATCH 1/8] drm/arm: Don't set allow_fb_modifiers explicitly Daniel Vetter
2021-04-27 9:20 ` [PATCH 2/8] drm/arm/malidp: Always list modifiers Daniel Vetter
2021-04-27 15:41 ` Liviu Dudau
2021-04-27 9:20 ` [PATCH 3/8] drm/i915: Don't set allow_fb_modifiers explicitly Daniel Vetter
2021-04-27 9:20 ` [PATCH 4/8] drm/msm/dpu1: " Daniel Vetter
2021-04-27 9:20 ` [PATCH 5/8] drm/msm/mdp4: Fix modifier support enabling Daniel Vetter
2021-04-27 9:20 ` [PATCH 6/8] drm/nouveau: Don't set allow_fb_modifiers explicitly Daniel Vetter
2021-04-27 9:20 ` [PATCH 7/8] drm/stm: " Daniel Vetter
2021-04-29 19:35 ` Philippe CORNU - foss
2021-04-27 9:20 ` [PATCH 8/8] drm/modifiers: Enforce consistency between the cap an IN_FORMATS Daniel Vetter
2021-04-27 9:30 ` Simon Ser
2021-04-27 11:32 ` Emil Velikov
2021-04-27 12:22 ` Daniel Vetter
2021-05-04 14:10 ` Emil Velikov
2021-05-04 14:58 ` Simon Ser
2021-05-04 15:48 ` Emil Velikov
2021-05-04 13:38 ` Pekka Paalanen
2021-05-05 19:24 ` Daniel Vetter [this message]
2021-05-06 9:55 ` Daniel Vetter
2021-04-27 15:25 ` [PATCH 1/8] drm/arm: Don't set allow_fb_modifiers explicitly Liviu Dudau
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