From: Helen Koike <helen.koike@collabora.com>
To: Boris Brezillon <boris.brezillon@collabora.com>
Cc: "Stéphane Marchesin" <marcheu@google.com>,
"Sean Paul" <seanpaul@google.com>,
"David Airlie" <airlied@linux.ie>,
daniel.vetter@ffwll.ch, linux-kernel@vger.kernel.org,
dri-devel@lists.freedesktop.org,
"Tomasz Figa" <tfiga@chromium.org>,
linux-rockchip@lists.infradead.org, kernel@collabora.com,
nicholas.kazlauskas@amd.com,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 1/5] drm/rockchip: fix fb references in async update
Date: Tue, 12 Mar 2019 12:34:45 -0300 [thread overview]
Message-ID: <f888a2d0-c6b1-8995-7254-ba2923dd22f9@collabora.com> (raw)
In-Reply-To: <20190312073438.05ad8173@collabora.com>
On 3/12/19 3:34 AM, Boris Brezillon wrote:
> On Mon, 11 Mar 2019 23:21:59 -0300
> Helen Koike <helen.koike@collabora.com> wrote:
>
>> In the case of async update, modifications are done in place, i.e. in the
>> current plane state, so the new_state is prepared and the new_state is
>> cleanup up (instead of the old_state, diferrently on what happen in a
>
> ^ cleaned up ^ differently (but maybe
> "unlike what happens" is more appropriate here).
>
>> normal sync update).
>> To cleanup the old_fb properly, it needs to be placed in the new_state
>> in the end of async_update, so cleanup call will unreference the old_fb
>> correctly.
>>
>> Also, the previous code had a:
>>
>> plane_state = plane->funcs->atomic_duplicate_state(plane);
>> ...
>> swap(plane_state, plane->state);
>>
>> if (plane->state->fb && plane->state->fb != new_state->fb) {
>> ...
>> }
>>
>> Which was wrong, as the fb were just assigned to be equal, so this if
>> statement nevers evaluates to true.
>>
>> Another details is that the function drm_crtc_vblank_get() can only be
>> called when vop->is_enabled is true, otherwise it has no effect and
>> trows a WARN_ON().
>>
>> Calling drm_atomic_set_fb_for_plane() (which get a referent of the new
>> fb and pus the old fb) is not required, as it is taken care by
>> drm_mode_cursor_universal() when calling
>> drm_atomic_helper_update_plane().
>>
>> Signed-off-by: Helen Koike <helen.koike@collabora.com>
>>
>> ---
>> Hello,
>>
>> I tested on the rockchip ficus v1.1 using igt plane_cursor_legacy and
>> kms_cursor_legacy and I didn't see any regressions.
>>
>> Changes in v2: None
>>
>> drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 42 ++++++++++++---------
>> 1 file changed, 24 insertions(+), 18 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>> index c7d4c6073ea5..a1ee8c156a7b 100644
>> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>> @@ -912,30 +912,31 @@ static void vop_plane_atomic_async_update(struct drm_plane *plane,
>> struct drm_plane_state *new_state)
>> {
>> struct vop *vop = to_vop(plane->state->crtc);
>> - struct drm_plane_state *plane_state;
>> + struct drm_framebuffer *old_fb = plane->state->fb;
>>
>> - plane_state = plane->funcs->atomic_duplicate_state(plane);
>> - plane_state->crtc_x = new_state->crtc_x;
>> - plane_state->crtc_y = new_state->crtc_y;
>> - plane_state->crtc_h = new_state->crtc_h;
>> - plane_state->crtc_w = new_state->crtc_w;
>> - plane_state->src_x = new_state->src_x;
>> - plane_state->src_y = new_state->src_y;
>> - plane_state->src_h = new_state->src_h;
>> - plane_state->src_w = new_state->src_w;
>> -
>> - if (plane_state->fb != new_state->fb)
>> - drm_atomic_set_fb_for_plane(plane_state, new_state->fb);
>> -
>> - swap(plane_state, plane->state);
>> -
>> - if (plane->state->fb && plane->state->fb != new_state->fb) {
>> + /*
>> + * A scanout can still be occurring, so we can't drop the reference to
>> + * the old framebuffer. To solve this we get a reference to old_fb and
>> + * set a worker to release it later.
>
> Hm, doesn't look like an async update to me if we have to wait for the
> next VBLANK to happen to get the new content on the screen. Maybe we
> should reject async updates when old_fb != new_fb in the rk
> ->async_check() hook.
Unless I am misunderstanding this, we don't wait here, we just grab a
reference to the fb in case it is being still used by the hw, so it
doesn't get released prematurely.
>
>> + */
>> + if (vop->is_enabled &&
>> + plane->state->fb && plane->state->fb != new_state->fb) {
>> drm_framebuffer_get(plane->state->fb);
>> WARN_ON(drm_crtc_vblank_get(plane->state->crtc) != 0);
>> drm_flip_work_queue(&vop->fb_unref_work, plane->state->fb);
>> set_bit(VOP_PENDING_FB_UNREF, &vop->pending);
>> }
>
> In any case, I think this should be called after
> vop_plane_atomic_update() to prevent the situation where the VBLANK
> event happens between this point and the following
> vop_plane_atomic_update() call.
ack, I'll update it in the next version.
>
>>
>> + plane->state->crtc_x = new_state->crtc_x;
>> + plane->state->crtc_y = new_state->crtc_y;
>> + plane->state->crtc_h = new_state->crtc_h;
>> + plane->state->crtc_w = new_state->crtc_w;
>> + plane->state->src_x = new_state->src_x;
>> + plane->state->src_y = new_state->src_y;
>> + plane->state->src_h = new_state->src_h;
>> + plane->state->src_w = new_state->src_w;
>> + plane->state->fb = new_state->fb;
>
> Any reason not to use swap() here and reference plane->state->fb
> instead of new_state->fb after this point?
I had the impression I had to do this in one of my tests, but re-testing
now and re-looking at the code this doesn't seem to be necessary. I'll
use a swap() in the next version.
Thanks for your feedback.
Helen
>
>> +
>> if (vop->is_enabled) {
>> rockchip_drm_psr_inhibit_get_state(new_state->state);
>> vop_plane_atomic_update(plane, plane->state);
>> @@ -945,7 +946,12 @@ static void vop_plane_atomic_async_update(struct drm_plane *plane,
>> rockchip_drm_psr_inhibit_put_state(new_state->state);
>> }
>>
>> - plane->funcs->atomic_destroy_state(plane, plane_state);
>> + /*
>> + * In async update we perform inplace modifications and release the
>> + * new_state. The following is required so we release the reference of
>> + * the old framebuffer.
>> + */
>> + new_state->fb = old_fb;
>> }
>>
>> static const struct drm_plane_helper_funcs plane_helper_funcs = {
>
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2019-03-12 15:34 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-12 2:21 [PATCH v2 0/5] drm: Fix fb changes for async updates Helen Koike
2019-03-12 2:21 ` [PATCH v2 1/5] drm/rockchip: fix fb references in async update Helen Koike
2019-03-12 6:34 ` Boris Brezillon
2019-03-12 11:04 ` Daniel Vetter
2019-03-12 15:34 ` Helen Koike [this message]
2019-03-12 15:52 ` Boris Brezillon
2019-03-13 3:42 ` Tomasz Figa
2019-03-13 9:58 ` Michel Dänzer
2019-03-13 18:08 ` Helen Koike
[not found] ` <ed44e1f4-07da-b1cb-b5cb-d34d29758502-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org>
2019-03-14 9:15 ` Michel Dänzer
2019-03-14 17:51 ` Helen Koike
2019-03-15 10:11 ` Michel Dänzer
2019-03-15 10:25 ` Boris Brezillon
2019-03-15 11:29 ` Michel Dänzer
2019-03-15 16:54 ` Helen Koike
[not found] ` <20190312022204.2775-1-helen.koike-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org>
2019-03-12 2:22 ` [PATCH v2 2/5] drm/amd: " Helen Koike
2019-03-12 2:22 ` [PATCH v2 3/5] drm/msm: " Helen Koike
2019-03-12 2:22 ` [PATCH v2 4/5] drm/vc4: " Helen Koike
2019-03-25 0:38 ` Sasha Levin
2019-03-12 2:22 ` [PATCH v2 5/5] drm: don't block fb changes for async plane updates Helen Koike
2019-03-12 6:44 ` Boris Brezillon
2019-03-12 12:49 ` Kazlauskas, Nicholas
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=f888a2d0-c6b1-8995-7254-ba2923dd22f9@collabora.com \
--to=helen.koike@collabora.com \
--cc=airlied@linux.ie \
--cc=boris.brezillon@collabora.com \
--cc=daniel.vetter@ffwll.ch \
--cc=dri-devel@lists.freedesktop.org \
--cc=kernel@collabora.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rockchip@lists.infradead.org \
--cc=marcheu@google.com \
--cc=nicholas.kazlauskas@amd.com \
--cc=seanpaul@google.com \
--cc=tfiga@chromium.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).