| Message ID | 20190314002027.7833-4-helen.koike@collabora.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm: Fix fb changes for async updates | expand |
On Wed, Mar 13, 2019 at 8:21 PM Helen Koike <helen.koike@collabora.com> wrote: > > Async update callbacks are expected to set the old_fb in the new_state > so prepare/cleanup framebuffers are balanced. > > Cc: <stable@vger.kernel.org> # v4.14+ > Fixes: 224a4c970987 ("drm/msm: update cursors asynchronously through atomic") > Suggested-by: Boris Brezillon <boris.brezillon@collabora.com> > Signed-off-by: Helen Koike <helen.koike@collabora.com> > > --- > Hello, > > As mentioned in the cover letter, > But I couldn't test on MSM because I don't have the hardware and I would > appreciate if anyone could test it. > > In other platforms (VC4, AMD, Rockchip), there is a hidden > drm_framebuffer_get(new_fb)/drm_framebuffer_put(old_fb) in async_update > that is wrong, but I couldn't identify those here, not sure if it is hidden > somewhere else, but if tests fail this is probably the cause. > > Thanks! > Helen Apologies, I haven't had a chance to test this yet, and it is likely to be a few weeks before I have a chance.. That said, not refcnt'ing the fb seems suspicious. I read the explanation in the other patches, but kind of think it is more clear to keep the extra refcnt'ing.. or at least have a comment. I do a bit wonder if we hold the ref to the outgoing cursor long enough.. I think the hw will actually continue to scan it out until the next vblank. But Archit was the one who added async_update support so maybe that is handled somewhere else. It's been a while since I've looked at this. BR, -R > > Changes in v3: None > Changes in v2: > - update CC stable and Fixes tag > > drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c > index be13140967b4..b854f471e9e5 100644 > --- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c > +++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c > @@ -502,6 +502,8 @@ static int mdp5_plane_atomic_async_check(struct drm_plane *plane, > static void mdp5_plane_atomic_async_update(struct drm_plane *plane, > struct drm_plane_state *new_state) > { > + struct drm_framebuffer *old_fb = plane->state->fb; > + > plane->state->src_x = new_state->src_x; > plane->state->src_y = new_state->src_y; > plane->state->crtc_x = new_state->crtc_x; > @@ -524,6 +526,8 @@ static void mdp5_plane_atomic_async_update(struct drm_plane *plane, > > *to_mdp5_plane_state(plane->state) = > *to_mdp5_plane_state(new_state); > + > + new_state->fb = old_fb; > } > > static const struct drm_plane_helper_funcs mdp5_plane_helper_funcs = { > -- > 2.20.1 >
Hi Rob, On 3/27/19 11:52 AM, Rob Clark wrote: > On Wed, Mar 13, 2019 at 8:21 PM Helen Koike <helen.koike@collabora.com> wrote: >> >> Async update callbacks are expected to set the old_fb in the new_state >> so prepare/cleanup framebuffers are balanced. >> >> Cc: <stable@vger.kernel.org> # v4.14+ >> Fixes: 224a4c970987 ("drm/msm: update cursors asynchronously through atomic") >> Suggested-by: Boris Brezillon <boris.brezillon@collabora.com> >> Signed-off-by: Helen Koike <helen.koike@collabora.com> >> >> --- >> Hello, >> >> As mentioned in the cover letter, >> But I couldn't test on MSM because I don't have the hardware and I would >> appreciate if anyone could test it. >> >> In other platforms (VC4, AMD, Rockchip), there is a hidden >> drm_framebuffer_get(new_fb)/drm_framebuffer_put(old_fb) in async_update >> that is wrong, but I couldn't identify those here, not sure if it is hidden >> somewhere else, but if tests fail this is probably the cause. >> >> Thanks! >> Helen > > Apologies, I haven't had a chance to test this yet, and it is likely > to be a few weeks before I have a chance.. > > That said, not refcnt'ing the fb seems suspicious. I read the > explanation in the other patches, but kind of think it is more clear > to keep the extra refcnt'ing.. or at least have a comment. Refcnt'ing is taken care by drm_mode_cursor_universal() when calling drm_atomic_helper_update_plane(). The other codes had a drm_atomic_set_fb_for_plane() (which get a referent of the new fb and put the old fb), but the problem is that the cleanup_plane will also put the ref of the old fb. In the other drivers I saw, drm_atomic_set_fb_for_plane() shouldn't be called, but this issue should be triggered very easily with a test. I can add this is in the async_check() docs. > > I do a bit wonder if we hold the ref to the outgoing cursor long > enough.. I think the hw will actually continue to scan it out until > the next vblank. But Archit was the one who added async_update > support so maybe that is handled somewhere else. It's been a while > since I've looked at this. I don't know much about MSM, but if I understand correctly, MSM don't support true async, is that correct? Then I think we need to do something similar to the rockchip: https://patchwork.kernel.org/patch/10852039/ and setup a drm_flip_work_queue(). But this seems another problem that is already there no? Not really related to this patch. I could send a separate patch for this (but I don't have the means to test it). Regards, Helen > > BR, > -R > > > >> >> Changes in v3: None >> Changes in v2: >> - update CC stable and Fixes tag >> >> drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c >> index be13140967b4..b854f471e9e5 100644 >> --- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c >> +++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c >> @@ -502,6 +502,8 @@ static int mdp5_plane_atomic_async_check(struct drm_plane *plane, >> static void mdp5_plane_atomic_async_update(struct drm_plane *plane, >> struct drm_plane_state *new_state) >> { >> + struct drm_framebuffer *old_fb = plane->state->fb; >> + >> plane->state->src_x = new_state->src_x; >> plane->state->src_y = new_state->src_y; >> plane->state->crtc_x = new_state->crtc_x; >> @@ -524,6 +526,8 @@ static void mdp5_plane_atomic_async_update(struct drm_plane *plane, >> >> *to_mdp5_plane_state(plane->state) = >> *to_mdp5_plane_state(new_state); >> + >> + new_state->fb = old_fb; >> } >> >> static const struct drm_plane_helper_funcs mdp5_plane_helper_funcs = { >> -- >> 2.20.1 >> >
Hello, On 3/13/19 9:20 PM, Helen Koike wrote: > Async update callbacks are expected to set the old_fb in the new_state > so prepare/cleanup framebuffers are balanced. > > Cc: <stable@vger.kernel.org> # v4.14+ > Fixes: 224a4c970987 ("drm/msm: update cursors asynchronously through atomic") > Suggested-by: Boris Brezillon <boris.brezillon@collabora.com> > Signed-off-by: Helen Koike <helen.koike@collabora.com> > > --- > Hello, > > As mentioned in the cover letter, > But I couldn't test on MSM because I don't have the hardware and I would > appreciate if anyone could test it. I got this tested on a dragonboard 410c, no regressions where found and no extra warnings. These two tests where already failing for other reasons: flip-vs-cursor-crc-atomic flip-vs-cursor-crc-legacy If you want to see the full log: https://people.collabora.com/~koike/drm-fixes-results.zip Thanks Helen > > In other platforms (VC4, AMD, Rockchip), there is a hidden > drm_framebuffer_get(new_fb)/drm_framebuffer_put(old_fb) in async_update > that is wrong, but I couldn't identify those here, not sure if it is hidden > somewhere else, but if tests fail this is probably the cause. > > Thanks! > Helen > > Changes in v3: None > Changes in v2: > - update CC stable and Fixes tag > > drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c > index be13140967b4..b854f471e9e5 100644 > --- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c > +++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c > @@ -502,6 +502,8 @@ static int mdp5_plane_atomic_async_check(struct drm_plane *plane, > static void mdp5_plane_atomic_async_update(struct drm_plane *plane, > struct drm_plane_state *new_state) > { > + struct drm_framebuffer *old_fb = plane->state->fb; > + > plane->state->src_x = new_state->src_x; > plane->state->src_y = new_state->src_y; > plane->state->crtc_x = new_state->crtc_x; > @@ -524,6 +526,8 @@ static void mdp5_plane_atomic_async_update(struct drm_plane *plane, > > *to_mdp5_plane_state(plane->state) = > *to_mdp5_plane_state(new_state); > + > + new_state->fb = old_fb; > } > > static const struct drm_plane_helper_funcs mdp5_plane_helper_funcs = { >
On Fri, May 31, 2019 at 10:54 AM Helen Koike <helen@koikeco.de> wrote: > > Hello, > > On 3/13/19 9:20 PM, Helen Koike wrote: > > Async update callbacks are expected to set the old_fb in the new_state > > so prepare/cleanup framebuffers are balanced. > > > > Cc: <stable@vger.kernel.org> # v4.14+ > > Fixes: 224a4c970987 ("drm/msm: update cursors asynchronously through atomic") > > Suggested-by: Boris Brezillon <boris.brezillon@collabora.com> > > Signed-off-by: Helen Koike <helen.koike@collabora.com> Thanks, I'm not super happy about the refcnt'ing subtleness here (mostly because it makes it harder to page in how things work on kernel/display side after spending most of my time in userspace/mesa), but I don't want to hold this up.. Acked-by: Rob Clark <robdclark@gmail.com> > > > > --- > > Hello, > > > > As mentioned in the cover letter, > > But I couldn't test on MSM because I don't have the hardware and I would > > appreciate if anyone could test it. > > I got this tested on a dragonboard 410c, no regressions where found and > no extra warnings. > > These two tests where already failing for other reasons: > flip-vs-cursor-crc-atomic > flip-vs-cursor-crc-legacy > > If you want to see the full log: > > https://people.collabora.com/~koike/drm-fixes-results.zip > > Thanks > Helen > > > > > In other platforms (VC4, AMD, Rockchip), there is a hidden > > drm_framebuffer_get(new_fb)/drm_framebuffer_put(old_fb) in async_update > > that is wrong, but I couldn't identify those here, not sure if it is hidden > > somewhere else, but if tests fail this is probably the cause. > > > > Thanks! > > Helen > > > > Changes in v3: None > > Changes in v2: > > - update CC stable and Fixes tag > > > > drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c > > index be13140967b4..b854f471e9e5 100644 > > --- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c > > +++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c > > @@ -502,6 +502,8 @@ static int mdp5_plane_atomic_async_check(struct drm_plane *plane, > > static void mdp5_plane_atomic_async_update(struct drm_plane *plane, > > struct drm_plane_state *new_state) > > { > > + struct drm_framebuffer *old_fb = plane->state->fb; > > + > > plane->state->src_x = new_state->src_x; > > plane->state->src_y = new_state->src_y; > > plane->state->crtc_x = new_state->crtc_x; > > @@ -524,6 +526,8 @@ static void mdp5_plane_atomic_async_update(struct drm_plane *plane, > > > > *to_mdp5_plane_state(plane->state) = > > *to_mdp5_plane_state(new_state); > > + > > + new_state->fb = old_fb; > > } > > > > static const struct drm_plane_helper_funcs mdp5_plane_helper_funcs = { > >
diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c index be13140967b4..b854f471e9e5 100644 --- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c +++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c @@ -502,6 +502,8 @@ static int mdp5_plane_atomic_async_check(struct drm_plane *plane, static void mdp5_plane_atomic_async_update(struct drm_plane *plane, struct drm_plane_state *new_state) { + struct drm_framebuffer *old_fb = plane->state->fb; + plane->state->src_x = new_state->src_x; plane->state->src_y = new_state->src_y; plane->state->crtc_x = new_state->crtc_x; @@ -524,6 +526,8 @@ static void mdp5_plane_atomic_async_update(struct drm_plane *plane, *to_mdp5_plane_state(plane->state) = *to_mdp5_plane_state(new_state); + + new_state->fb = old_fb; } static const struct drm_plane_helper_funcs mdp5_plane_helper_funcs = {
Async update callbacks are expected to set the old_fb in the new_state so prepare/cleanup framebuffers are balanced. Cc: <stable@vger.kernel.org> # v4.14+ Fixes: 224a4c970987 ("drm/msm: update cursors asynchronously through atomic") Suggested-by: Boris Brezillon <boris.brezillon@collabora.com> Signed-off-by: Helen Koike <helen.koike@collabora.com> --- Hello, As mentioned in the cover letter, But I couldn't test on MSM because I don't have the hardware and I would appreciate if anyone could test it. In other platforms (VC4, AMD, Rockchip), there is a hidden drm_framebuffer_get(new_fb)/drm_framebuffer_put(old_fb) in async_update that is wrong, but I couldn't identify those here, not sure if it is hidden somewhere else, but if tests fail this is probably the cause. Thanks! Helen Changes in v3: None Changes in v2: - update CC stable and Fixes tag drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c | 4 ++++ 1 file changed, 4 insertions(+)