Re: [PATCH 3/3] drm/atomic: Rename crtc_state->pageflip_flags to async_flip

From: Daniel Vetter <daniel.vetter@ffwll.ch>
To: Mario Kleiner <mario.kleiner.de@gmail.com>
Cc: "Sam Ravnborg" <sam@ravnborg.org>,
	"Koenig, Christian" <Christian.Koenig@amd.com>,
	"David Airlie" <airlied@linux.ie>,
	"Michel Dänzer" <michel@daenzer.net>,
	"Li, Sun peng (Leo)" <Sunpeng.Li@amd.com>,
	"DRI Development" <dri-devel@lists.freedesktop.org>,
	"Kazlauskas, Nicholas" <Nicholas.Kazlauskas@amd.com>,
	"Lakha, Bhawanpreet" <Bhawanpreet.Lakha@amd.com>,
	"Maxime Ripard" <maxime.ripard@bootlin.com>,
	"Ben Skeggs" <bskeggs@redhat.com>,
	"Francis, David" <David.Francis@amd.com>,
	"Daniel Vetter" <daniel.vetter@intel.com>,
	"Sean Paul" <sean@poorly.run>,
	"Intel Graphics Development" <intel-gfx@lists.freedesktop.org>
Subject: Re: [PATCH 3/3] drm/atomic: Rename crtc_state->pageflip_flags to async_flip
Date: Thu, 5 Sep 2019 15:58:47 +0200	[thread overview]
Message-ID: <CAKMK7uEpgVc4CG7g0r_6iHLMQeb3ox4v8CO8peEU6Pn8Qvi+Xg@mail.gmail.com> (raw)
In-Reply-To: <CAEsyxyjM71CuDbYrniH70Eg_Xd_r_yd3eBDtiv9z1SKcpOKKCQ@mail.gmail.com>

On Thu, Sep 5, 2019 at 2:33 PM Mario Kleiner <mario.kleiner.de@gmail.com> wrote:
> On Wed, Sep 4, 2019 at 2:57 PM Kazlauskas, Nicholas
> <Nicholas.Kazlauskas@amd.com> wrote:
> >
> > On 2019-09-03 3:06 p.m., Daniel Vetter wrote:
> > > It's the only flag anyone actually cares about. Plus if we're unlucky,
> > > the atomic ioctl might need a different flag for async flips. So
> > > better to abstract this away from the uapi a bit.
> > >
> > > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> > > Cc: Michel Dänzer <michel@daenzer.net>
> > > Cc: Alex Deucher <alexdeucher@gmail.com>
> > > Cc: Adam Jackson <ajax@redhat.com>
> > > Cc: Sean Paul <sean@poorly.run>
> > > Cc: David Airlie <airlied@linux.ie>
> > > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> > > Cc: Maxime Ripard <maxime.ripard@bootlin.com>
> > > Cc: Daniel Vetter <daniel@ffwll.ch>
> > > Cc: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
> > > Cc: Leo Li <sunpeng.li@amd.com>
> > > Cc: Harry Wentland <harry.wentland@amd.com>
> > > Cc: David Francis <David.Francis@amd.com>
> > > Cc: Mario Kleiner <mario.kleiner.de@gmail.com>
> > > Cc: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
> > > Cc: Ben Skeggs <bskeggs@redhat.com>
> > > Cc: "Christian König" <christian.koenig@amd.com>
> > > Cc: Ilia Mirkin <imirkin@alum.mit.edu>
> > > Cc: Sam Ravnborg <sam@ravnborg.org>
> > > Cc: Chris Wilson <chris@chris-wilson.co.uk>
> > > ---
> >
> > Series is:
> >
> > Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
> >
> > I would like to see a new flag eventually show up for atomic as well,
> > but the existing one is effectively broken at this point and I would
> > hope that no userspace is setting it expecting that it actually does
> > something.
>
> You mean it is generally broken? My software uses non-vsync'ed flips
> for diagnostic purpose and iirc some gpu + driver combo didn't work as
> expected anymore. But i thought that was one specific driver bug
> (maybe on AMD + DC)?

atomic ioctl + FLIP_ASYNC does not do anything special. FLIP_ASYNC
with the legacy page_flip ioctl works correctly. This is in the core
ioctl handler (the flag simply did nothing for atomic), so
irrespective of whether the driver has a bug or not with FLIP_ASYNC.

> > At this point we don't really gain anything from enabling atomic in DDX
> > I think, most drivers already make use of DRM helpers to map these
> > legacy IOCTLs to atomic anyway.
> >
>
> One thing i wanted to try, once i hopefully find some time in late
> 2019 / early 2020 (if nobody else starts working on such a thing
> earlier), would be to add the ability to pass in a target flip time to
> the pageflip ioctl for use with VRR. For that i thought adding a new
> pageflip flag a la DRM_MODE_PAGE_FLIP_TARGETTIME) would be a good way
> to reuse the existing page_flip_target ioctl and redefine the "uint32
> sequence" field of struct drm_mode_crtc_page_flip_target to pass in
> the target time - or at least the lower 32 bits of a target time.

Yeah target time (instead of just target vblank that we currently
have) has been discussed before. It's just that no one yet typed an
implementation (driver and userspace and all that).

> So that would be one more page flip flag for the future. I'd like this
> to be workable from X11, and the current DDX don't use the atomic
> interface, apart from the modesetting DDX where it just got disabled
> by default in xserver master due to various unresolved bugs afaik?

It was a bit too simplistic a conversion. But for specific features
(like doing a page flip with atomic instead of the legacy page_flip
ioctl because you need that one new feature) you can just use the
atomic ioctl - legacy ioctl and atomic can be mixed like that, because
underneath it's all atomic anyway.

The trouble with the modesetting atomic is that atomic isn't a simple
1:1 translation of the old ioctls, and the implementation that landed
was simply broken. And no one has put in the work to make it solid, so
it got backed out.
-Daniel

>
> thanks,
> -mario
>
> > Nicholas Kazlauskas
> >
> > >   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 5 ++---
> > >   drivers/gpu/drm/drm_atomic_helper.c               | 2 +-
> > >   drivers/gpu/drm/drm_atomic_state_helper.c         | 2 +-
> > >   drivers/gpu/drm/nouveau/dispnv50/wndw.c           | 4 ++--
> > >   include/drm/drm_crtc.h                            | 8 ++++----
> > >   5 files changed, 10 insertions(+), 11 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > > index 0a71ed1e7762..2f0ef0820f00 100644
> > > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > > @@ -5756,8 +5756,7 @@ static void amdgpu_dm_commit_planes(struct drm_atomic_state *state,
> > >                * change FB pitch, DCC state, rotation or mirroing.
> > >                */
> > >               bundle->flip_addrs[planes_count].flip_immediate =
> > > -                     (crtc->state->pageflip_flags &
> > > -                      DRM_MODE_PAGE_FLIP_ASYNC) != 0 &&
> > > +                     crtc->state->async_flip &&
> > >                       acrtc_state->update_type == UPDATE_TYPE_FAST;
> > >
> > >               timestamp_ns = ktime_get_ns();
> > > @@ -6334,7 +6333,7 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
> > >       amdgpu_dm_enable_crtc_interrupts(dev, state, true);
> > >
> > >       for_each_new_crtc_in_state(state, crtc, new_crtc_state, j)
> > > -             if (new_crtc_state->pageflip_flags & DRM_MODE_PAGE_FLIP_ASYNC)
> > > +             if (new_crtc_state->async_flip)
> > >                       wait_for_vblank = false;
> > >
> > >       /* update planes when needed per crtc*/
> > > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> > > index e9c6112e7f73..1e5293eb66e3 100644
> > > --- a/drivers/gpu/drm/drm_atomic_helper.c
> > > +++ b/drivers/gpu/drm/drm_atomic_helper.c
> > > @@ -3263,7 +3263,7 @@ static int page_flip_common(struct drm_atomic_state *state,
> > >               return PTR_ERR(crtc_state);
> > >
> > >       crtc_state->event = event;
> > > -     crtc_state->pageflip_flags = flags;
> > > +     crtc_state->async_flip = flags & DRM_MODE_PAGE_FLIP_ASYNC;
> > >
> > >       plane_state = drm_atomic_get_plane_state(state, plane);
> > >       if (IS_ERR(plane_state))
> > > diff --git a/drivers/gpu/drm/drm_atomic_state_helper.c b/drivers/gpu/drm/drm_atomic_state_helper.c
> > > index 46dc264a248b..d0a937fb0c56 100644
> > > --- a/drivers/gpu/drm/drm_atomic_state_helper.c
> > > +++ b/drivers/gpu/drm/drm_atomic_state_helper.c
> > > @@ -128,7 +128,7 @@ void __drm_atomic_helper_crtc_duplicate_state(struct drm_crtc *crtc,
> > >       state->zpos_changed = false;
> > >       state->commit = NULL;
> > >       state->event = NULL;
> > > -     state->pageflip_flags = 0;
> > > +     state->async_flip = false;
> > >
> > >       /* Self refresh should be canceled when a new update is available */
> > >       state->active = drm_atomic_crtc_effectively_active(state);
> > > diff --git a/drivers/gpu/drm/nouveau/dispnv50/wndw.c b/drivers/gpu/drm/nouveau/dispnv50/wndw.c
> > > index 2db029371c91..5193b6257061 100644
> > > --- a/drivers/gpu/drm/nouveau/dispnv50/wndw.c
> > > +++ b/drivers/gpu/drm/nouveau/dispnv50/wndw.c
> > > @@ -267,7 +267,7 @@ nv50_wndw_atomic_check_acquire(struct nv50_wndw *wndw, bool modeset,
> > >                       asyw->image.pitch[0] = fb->base.pitches[0];
> > >               }
> > >
> > > -             if (!(asyh->state.pageflip_flags & DRM_MODE_PAGE_FLIP_ASYNC))
> > > +             if (!asyh->state.async_flip)
> > >                       asyw->image.interval = 1;
> > >               else
> > >                       asyw->image.interval = 0;
> > > @@ -383,7 +383,7 @@ nv50_wndw_atomic_check_lut(struct nv50_wndw *wndw,
> > >       }
> > >
> > >       /* Can't do an immediate flip while changing the LUT. */
> > > -     asyh->state.pageflip_flags &= ~DRM_MODE_PAGE_FLIP_ASYNC;
> > > +     asyh->state.async_flip = false;
> > >   }
> > >
> > >   static int
> > > diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> > > index 7e2963cad543..900ae8d452b8 100644
> > > --- a/include/drm/drm_crtc.h
> > > +++ b/include/drm/drm_crtc.h
> > > @@ -284,12 +284,12 @@ struct drm_crtc_state {
> > >       u32 target_vblank;
> > >
> > >       /**
> > > -      * @pageflip_flags:
> > > +      * @async_flip:
> > >        *
> > > -      * DRM_MODE_PAGE_FLIP_* flags, as passed to the page flip ioctl.
> > > -      * Zero in any other case.
> > > +      * This is set when DRM_MODE_PAGE_FLIP_ASYNC is set in the legacy
> > > +      * PAGE_FLIP IOCTL. It's not wired up for the atomic IOCTL itself yet.
> > >        */
> > > -     u32 pageflip_flags;
> > > +     bool async_flip;
> > >
> > >       /**
> > >        * @vrr_enabled:
> > >
> >

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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