| Message ID | 20210414090815.453744-1-daniel.vetter@ffwll.ch (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/modifiers: Enforce consistency between the cap an IN_FORMATS | expand |
On Wed, 14 Apr 2021 11:08:15 +0200 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> > --- > 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: > * Acked-by: Pekka Paalanen <pekka.paalanen@collabora.com> Thanks, pq
Reviewed-by: Simon Ser <contact@emersion.fr>
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: *