| Message ID | 20210622165511.3169559-8-daniel.vetter@ffwll.ch (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | implicit fencing/dma-resv rules for shared buffers | expand |
Hi Daniel, On Tue, Jun 22, 2021 at 06:55:03PM +0200, Daniel Vetter wrote: > There's a bunch of atomic drivers who don't do this quite correctly, > luckily most of them aren't in wide use or people would have noticed > the tearing. > > By making this the default we avoid the constant audit pain and can > additionally remove a ton of lines from vfuncs for a bit more clarity > in smaller drivers. > > While at it complain if there's a cleanup_fb hook but no prepare_fb > hook, because that makes no sense. I haven't found any driver which > violates this, but better safe than sorry. > > Subsequent patches will reap the benefits. > > 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_atomic_helper.c | 10 ++++++++++ > drivers/gpu/drm/drm_gem_atomic_helper.c | 3 +++ > include/drm/drm_modeset_helper_vtables.h | 7 +++++-- > 3 files changed, 18 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c > index 531f2374b072..9f6c5f21c4d6 100644 > --- a/drivers/gpu/drm/drm_atomic_helper.c > +++ b/drivers/gpu/drm/drm_atomic_helper.c > @@ -35,6 +35,7 @@ > #include <drm/drm_damage_helper.h> > #include <drm/drm_device.h> > #include <drm/drm_drv.h> > +#include <drm/drm_gem_atomic_helper.h> > #include <drm/drm_plane_helper.h> > #include <drm/drm_print.h> > #include <drm/drm_self_refresh_helper.h> > @@ -2408,6 +2409,15 @@ int drm_atomic_helper_prepare_planes(struct drm_device *dev, > ret = funcs->prepare_fb(plane, new_plane_state); > if (ret) > goto fail; > + } else { > + WARN_ON_ONCE(funcs->cleanup_fb); > + > + if (!drm_core_check_feature(dev, DRIVER_GEM)) > + continue; > + > + ret = drm_gem_plane_helper_prepare_fb(plane, new_plane_state); > + if (ret) > + goto fail; > } > } > > diff --git a/drivers/gpu/drm/drm_gem_atomic_helper.c b/drivers/gpu/drm/drm_gem_atomic_helper.c > index a27135084ae5..bc9396f2a0ed 100644 > --- a/drivers/gpu/drm/drm_gem_atomic_helper.c > +++ b/drivers/gpu/drm/drm_gem_atomic_helper.c > @@ -135,6 +135,9 @@ > * GEM based framebuffer drivers which have their buffers always pinned in > * memory. > * > + * This function is the default implementation for GEM drivers of > + * &drm_plane_helper_funcs.prepare_fb if no callback is provided. > + * > * See drm_atomic_set_fence_for_plane() for a discussion of implicit and > * explicit fencing in atomic modeset updates. > */ > diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h > index f3a4b47b3986..4e727261dca5 100644 > --- a/include/drm/drm_modeset_helper_vtables.h > +++ b/include/drm/drm_modeset_helper_vtables.h > @@ -1178,8 +1178,11 @@ struct drm_plane_helper_funcs { > * equivalent functionality should be implemented through private > * members in the plane structure. > * > - * Drivers which always have their buffers pinned should use > - * drm_gem_plane_helper_prepare_fb() for this hook. > + * For GEM drivers who neither have a @prepare_fb not @cleanup_fb hook s/not/nor/ ?? > + * set drm_gem_plane_helper_prepare_fb() is called automatically to ^add comma? > + * implement this. Leave cleanup_fb out of the description to make it more readable. In the description of cleanup_fb you can document that it is wrong to have it without a matcching prepare_fb if you feel for it. Sam * Other drivers which need additional plane processing > + * can call drm_gem_plane_helper_prepare_fb() from their @prepare_fb > + * hook. > * > * The helpers will call @cleanup_fb with matching arguments for every > * successful call to this hook. > -- > 2.32.0.rc2
On Tue, Jun 22, 2021 at 9:10 PM Sam Ravnborg <sam@ravnborg.org> wrote: > > Hi Daniel, > > On Tue, Jun 22, 2021 at 06:55:03PM +0200, Daniel Vetter wrote: > > There's a bunch of atomic drivers who don't do this quite correctly, > > luckily most of them aren't in wide use or people would have noticed > > the tearing. > > > > By making this the default we avoid the constant audit pain and can > > additionally remove a ton of lines from vfuncs for a bit more clarity > > in smaller drivers. > > > > While at it complain if there's a cleanup_fb hook but no prepare_fb > > hook, because that makes no sense. I haven't found any driver which > > violates this, but better safe than sorry. > > > > Subsequent patches will reap the benefits. > > > > 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_atomic_helper.c | 10 ++++++++++ > > drivers/gpu/drm/drm_gem_atomic_helper.c | 3 +++ > > include/drm/drm_modeset_helper_vtables.h | 7 +++++-- > > 3 files changed, 18 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c > > index 531f2374b072..9f6c5f21c4d6 100644 > > --- a/drivers/gpu/drm/drm_atomic_helper.c > > +++ b/drivers/gpu/drm/drm_atomic_helper.c > > @@ -35,6 +35,7 @@ > > #include <drm/drm_damage_helper.h> > > #include <drm/drm_device.h> > > #include <drm/drm_drv.h> > > +#include <drm/drm_gem_atomic_helper.h> > > #include <drm/drm_plane_helper.h> > > #include <drm/drm_print.h> > > #include <drm/drm_self_refresh_helper.h> > > @@ -2408,6 +2409,15 @@ int drm_atomic_helper_prepare_planes(struct drm_device *dev, > > ret = funcs->prepare_fb(plane, new_plane_state); > > if (ret) > > goto fail; > > + } else { > > + WARN_ON_ONCE(funcs->cleanup_fb); > > + > > + if (!drm_core_check_feature(dev, DRIVER_GEM)) > > + continue; > > + > > + ret = drm_gem_plane_helper_prepare_fb(plane, new_plane_state); > > + if (ret) > > + goto fail; > > } > > } > > > > diff --git a/drivers/gpu/drm/drm_gem_atomic_helper.c b/drivers/gpu/drm/drm_gem_atomic_helper.c > > index a27135084ae5..bc9396f2a0ed 100644 > > --- a/drivers/gpu/drm/drm_gem_atomic_helper.c > > +++ b/drivers/gpu/drm/drm_gem_atomic_helper.c > > @@ -135,6 +135,9 @@ > > * GEM based framebuffer drivers which have their buffers always pinned in > > * memory. > > * > > + * This function is the default implementation for GEM drivers of > > + * &drm_plane_helper_funcs.prepare_fb if no callback is provided. > > + * > > * See drm_atomic_set_fence_for_plane() for a discussion of implicit and > > * explicit fencing in atomic modeset updates. > > */ > > diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h > > index f3a4b47b3986..4e727261dca5 100644 > > --- a/include/drm/drm_modeset_helper_vtables.h > > +++ b/include/drm/drm_modeset_helper_vtables.h > > @@ -1178,8 +1178,11 @@ struct drm_plane_helper_funcs { > > * equivalent functionality should be implemented through private > > * members in the plane structure. > > * > > - * Drivers which always have their buffers pinned should use > > - * drm_gem_plane_helper_prepare_fb() for this hook. > > + * For GEM drivers who neither have a @prepare_fb not @cleanup_fb hook > s/not/nor/ ?? Yup. > > + * set drm_gem_plane_helper_prepare_fb() is called automatically to > ^add comma? > > + * implement this. > > > Leave cleanup_fb out of the description to make it more readable. With the not->nor typo fixed, why does this make it more readable? Afaiui neither ... nor ... is fairly standard English, and I really want to make this the default only if you specify absolutely no plane fb handling of your own. > In the description of cleanup_fb you can document that it is wrong to > have it without a matcching prepare_fb if you feel for it. So the reason I didn't document things that way is that imo the "cleanup_fb but not prepare_fb" case is just nonsense. But I also didn't want to accidentally paper over bugs where people set only cleanup_fb and forget to hook up the other one, hence the warning. But if you think we should explain that in docs, I guess I can shuffle it around. Just feel like specifying everything in the comments doesn't help the readability of the docs. -Daniel > > Sam > > > * Other drivers which need additional plane processing > > + * can call drm_gem_plane_helper_prepare_fb() from their @prepare_fb > > + * hook. > > * > > * The helpers will call @cleanup_fb with matching arguments for every > > * successful call to this hook. > > -- > > 2.32.0.rc2
Hi Daniel, > > > * equivalent functionality should be implemented through private > > > * members in the plane structure. > > > * > > > - * Drivers which always have their buffers pinned should use > > > - * drm_gem_plane_helper_prepare_fb() for this hook. > > > + * For GEM drivers who neither have a @prepare_fb not @cleanup_fb hook > > s/not/nor/ ?? > > Yup. > > > > + * set drm_gem_plane_helper_prepare_fb() is called automatically to > > ^add comma? > > > + * implement this. > > > > > > Leave cleanup_fb out of the description to make it more readable. > > With the not->nor typo fixed, why does this make it more readable? > Afaiui neither ... nor ... is fairly standard English, and I really > want to make this the default only if you specify absolutely no plane > fb handling of your own. What I tried to suggest was like this: " Drivers which always have their buffers pinned should use drm_gem_plane_helper_prepare_fb() for this hook. For GEM drivers who do not have a @prepare_fb hook set, drm_gem_plane_helper_prepare_fb() is called automatically to implement this. " But anyway is fine and with the typo fixed: Acked-by: Sam Ravnborg <sam@ravnborg.org> Sam
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 531f2374b072..9f6c5f21c4d6 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -35,6 +35,7 @@ #include <drm/drm_damage_helper.h> #include <drm/drm_device.h> #include <drm/drm_drv.h> +#include <drm/drm_gem_atomic_helper.h> #include <drm/drm_plane_helper.h> #include <drm/drm_print.h> #include <drm/drm_self_refresh_helper.h> @@ -2408,6 +2409,15 @@ int drm_atomic_helper_prepare_planes(struct drm_device *dev, ret = funcs->prepare_fb(plane, new_plane_state); if (ret) goto fail; + } else { + WARN_ON_ONCE(funcs->cleanup_fb); + + if (!drm_core_check_feature(dev, DRIVER_GEM)) + continue; + + ret = drm_gem_plane_helper_prepare_fb(plane, new_plane_state); + if (ret) + goto fail; } } diff --git a/drivers/gpu/drm/drm_gem_atomic_helper.c b/drivers/gpu/drm/drm_gem_atomic_helper.c index a27135084ae5..bc9396f2a0ed 100644 --- a/drivers/gpu/drm/drm_gem_atomic_helper.c +++ b/drivers/gpu/drm/drm_gem_atomic_helper.c @@ -135,6 +135,9 @@ * GEM based framebuffer drivers which have their buffers always pinned in * memory. * + * This function is the default implementation for GEM drivers of + * &drm_plane_helper_funcs.prepare_fb if no callback is provided. + * * See drm_atomic_set_fence_for_plane() for a discussion of implicit and * explicit fencing in atomic modeset updates. */ diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h index f3a4b47b3986..4e727261dca5 100644 --- a/include/drm/drm_modeset_helper_vtables.h +++ b/include/drm/drm_modeset_helper_vtables.h @@ -1178,8 +1178,11 @@ struct drm_plane_helper_funcs { * equivalent functionality should be implemented through private * members in the plane structure. * - * Drivers which always have their buffers pinned should use - * drm_gem_plane_helper_prepare_fb() for this hook. + * For GEM drivers who neither have a @prepare_fb not @cleanup_fb hook + * set drm_gem_plane_helper_prepare_fb() is called automatically to + * implement this. Other drivers which need additional plane processing + * can call drm_gem_plane_helper_prepare_fb() from their @prepare_fb + * hook. * * The helpers will call @cleanup_fb with matching arguments for every * successful call to this hook.
There's a bunch of atomic drivers who don't do this quite correctly, luckily most of them aren't in wide use or people would have noticed the tearing. By making this the default we avoid the constant audit pain and can additionally remove a ton of lines from vfuncs for a bit more clarity in smaller drivers. While at it complain if there's a cleanup_fb hook but no prepare_fb hook, because that makes no sense. I haven't found any driver which violates this, but better safe than sorry. Subsequent patches will reap the benefits. 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_atomic_helper.c | 10 ++++++++++ drivers/gpu/drm/drm_gem_atomic_helper.c | 3 +++ include/drm/drm_modeset_helper_vtables.h | 7 +++++-- 3 files changed, 18 insertions(+), 2 deletions(-)