On Thu, Oct 4, 2018 at 11:14 PM Sam Ravnborg <sam@xxxxxxxxxxxx> wrote:
>
> Hi Daniel.
>
> On Thu, Oct 04, 2018 at 10:24:43PM +0200, Daniel Vetter wrote:
> > Well except the destroy helper, which isn't really a primary helper
> > but generally useful, if mislabelled.
> >
> > Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> > Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
> > ---
> > drivers/gpu/drm/drm_plane_helper.c | 85 ++++--------------------------
> > include/drm/drm_plane_helper.h | 10 ----
> > 2 files changed, 11 insertions(+), 84 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_plane_helper.c b/drivers/gpu/drm/drm_plane_helper.c
> > index 33b3e6892787..0fff72dcd06d 100644
> > --- a/drivers/gpu/drm/drm_plane_helper.c
> > +++ b/drivers/gpu/drm/drm_plane_helper.c
> > @@ -42,11 +42,8 @@
> > * primary plane support on top of the normal CRTC configuration interface.
> > * Since the legacy &drm_mode_config_funcs.set_config interface ties the primary
> > * plane together with the CRTC state this does not allow userspace to disable
> > - * the primary plane itself. To avoid too much duplicated code use
> > - * drm_plane_helper_check_update() which can be used to enforce the same
> > - * restrictions as primary planes had thus. The default primary plane only
> > - * expose XRBG8888 and ARGB8888 as valid pixel formats for the attached
> > - * framebuffer.
> > + * the primary plane itself. The default primary plane only expose XRBG8888 and
> > + * ARGB8888 as valid pixel formats for the attached framebuffer.
> > *
> > * Drivers are highly recommended to implement proper support for primary
> > * planes, and newly merged drivers must not rely upon these transitional
> > @@ -148,50 +145,13 @@ static int drm_plane_helper_check_update(struct drm_plane *plane,
> > return 0;
> > }
> >
> > -/**
> > - * drm_primary_helper_update() - Helper for primary plane update
> > - * @plane: plane object to update
> > - * @crtc: owning CRTC of owning plane
> > - * @fb: framebuffer to flip onto plane
> > - * @crtc_x: x offset of primary plane on crtc
> > - * @crtc_y: y offset of primary plane on crtc
> > - * @crtc_w: width of primary plane rectangle on crtc
> > - * @crtc_h: height of primary plane rectangle on crtc
> > - * @src_x: x offset of @fb for panning
> > - * @src_y: y offset of @fb for panning
> > - * @src_w: width of source rectangle in @fb
> > - * @src_h: height of source rectangle in @fb
> > - * @ctx: lock acquire context, not used here
> > - *
> > - * Provides a default plane update handler for primary planes. This is handler
> > - * is called in response to a userspace SetPlane operation on the plane with a
> > - * non-NULL framebuffer. We call the driver's modeset handler to update the
> > - * framebuffer.
> > - *
> > - * SetPlane() on a primary plane of a disabled CRTC is not supported, and will
> > - * return an error.
> > - *
> > - * Note that we make some assumptions about hardware limitations that may not be
> > - * true for all hardware --
> > - *
> > - * 1. Primary plane cannot be repositioned.
> > - * 2. Primary plane cannot be scaled.
> > - * 3. Primary plane must cover the entire CRTC.
> > - * 4. Subpixel positioning is not supported.
> > - *
> > - * Drivers for hardware that don't have these restrictions can provide their
> > - * own implementation rather than using this helper.
> > - *
> > - * RETURNS:
> > - * Zero on success, error code on failure
> > - */
> > -int drm_primary_helper_update(struct drm_plane *plane, struct drm_crtc *crtc,
> > - struct drm_framebuffer *fb,
> > - int crtc_x, int crtc_y,
> > - unsigned int crtc_w, unsigned int crtc_h,
> > - uint32_t src_x, uint32_t src_y,
> > - uint32_t src_w, uint32_t src_h,
> > - struct drm_modeset_acquire_ctx *ctx)
> > +static int drm_primary_helper_update(struct drm_plane *plane, struct drm_crtc *crtc,
>
> This looks like a useful comment explaining the purpose
> of a function get lost.
Hm, good point, some of this could be moved into drm_crtc_init().
Maybe with a stern warning that you really don't want this for a new
driver. The current kernel-doc there is rather sparse.
> > + struct drm_framebuffer *fb,
> > + int crtc_x, int crtc_y,
> > + unsigned int crtc_w, unsigned int crtc_h,
> > + uint32_t src_x, uint32_t src_y,
> > + uint32_t src_w, uint32_t src_h,
> > + struct drm_modeset_acquire_ctx *ctx)
> > {
> > struct drm_mode_set set = {
> > .crtc = crtc,
> > @@ -258,35 +218,12 @@ int drm_primary_helper_update(struct drm_plane *plane, struct drm_crtc *crtc,
> > kfree(connector_list);
> > return ret;
> > }
> > -EXPORT_SYMBOL(drm_primary_helper_update);
> >
> > -/**
> > - * drm_primary_helper_disable() - Helper for primary plane disable
> > - * @plane: plane to disable
> > - * @ctx: lock acquire context, not used here
> > - *
> > - * Provides a default plane disable handler for primary planes. This is handler
> > - * is called in response to a userspace SetPlane operation on the plane with a
> > - * NULL framebuffer parameter. It unconditionally fails the disable call with
> > - * -EINVAL the only way to disable the primary plane without driver support is
> > - * to disable the entire CRTC. Which does not match the plane
> > - * &drm_plane_funcs.disable_plane hook.
> > - *
> > - * Note that some hardware may be able to disable the primary plane without
> > - * disabling the whole CRTC. Drivers for such hardware should provide their
> > - * own disable handler that disables just the primary plane (and they'll likely
> > - * need to provide their own update handler as well to properly re-enable a
> > - * disabled primary plane).
> > - *
> > - * RETURNS:
> > - * Unconditionally returns -EINVAL.
> > - */
> > -int drm_primary_helper_disable(struct drm_plane *plane,
> > - struct drm_modeset_acquire_ctx *ctx)
> > +static int drm_primary_helper_disable(struct drm_plane *plane,
> > + struct drm_modeset_acquire_ctx *ctx)
> > {
> > return -EINVAL;
> > }
> Likewise, good comment deleted. But then in this case this is also
> nicely commented where disable_plane is called.
> The single use of disable_plane could also just check for NULL,
> that would be more straightforward and then this functions could be deleted.
Returning -EINVAL unconditionally is really not what any new or modern
driver should ever do. Atomic drivers need to hook up
drm_atomic_helper_plane_disable(), legacy drivers who care about
planes also really want their own implementation here. Imo { return
-EINVAL; } is the worst choice of a default we can pick, since it
would mislead a lot of drivers into doing the wrong thing.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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