From: Sam Ravnborg <sam@ravnborg.org>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: dri-devel@lists.freedesktop.org,
Andrzej Hajda <andrzej.hajda@intel.com>,
Chun-Kuang Hu <chunkuang.hu@kernel.org>,
Dafna Hirschfeld <dafna.hirschfeld@collabora.com>,
Daniel Vetter <daniel@ffwll.ch>, David Airlie <airlied@linux.ie>,
Enric Balletbo i Serra <enric.balletbo@collabora.com>,
Jernej Skrabec <jernej.skrabec@gmail.com>,
Jitao Shi <jitao.shi@mediatek.com>,
Jonas Karlman <jonas@kwiboo.se>,
linux-arm-kernel@lists.infradead.org,
linux-mediatek@lists.infradead.org,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Matthias Brugger <matthias.bgg@gmail.com>,
Maxime Ripard <mripard@kernel.org>,
Neil Armstrong <narmstrong@baylibre.com>,
Philip Chen <philipchen@chromium.org>,
Philipp Zabel <p.zabel@pengutronix.de>,
Robert Foss <robert.foss@linaro.org>,
Thomas Zimmermann <tzimmermann@suse.de>,
Maxime Ripard <maxime@cerno.tech>,
Andrzej Hajda <a.hajda@samsung.com>
Subject: Re: [PATCH v2 1/7] drm/bridge: ps8640: Use atomic variants of drm_bridge_funcs
Date: Fri, 22 Oct 2021 18:53:02 +0200 [thread overview]
Message-ID: <YXLsbp+IwiRYfY2a@ravnborg.org> (raw)
In-Reply-To: <YXLHlaLfPD4wI7R7@pendragon.ideasonboard.com>
Hi Laurent,
> > @@ -508,8 +510,8 @@ static const struct drm_bridge_funcs ps8640_bridge_funcs = {
> > .attach = ps8640_bridge_attach,
> > .detach = ps8640_bridge_detach,
> > .get_edid = ps8640_bridge_get_edid,
> > - .post_disable = ps8640_post_disable,
> > - .pre_enable = ps8640_pre_enable,
> > + .atomic_post_disable = ps8640_atomic_post_disable,
> > + .atomic_pre_enable = ps8640_atomic_pre_enable,
>
> Don't you also need to implement .atomic_duplicate_state(),
> .atomic_destroy_state() and .atomic_reset() to use the atomic API ?
What I think happens is that the atomic drivers uses the bridges and
the implementation in drm_bridge has fall-backs to the non-atomic
variants.
So for example drm_atomic_bridge_chain_pre_enable() will call
atomic_pre_enable() if it exists, and if not it will call pre_enable()
if it exists.
With this patch-set I show that the non-atomic versions of several of
the drm_bridge helper functions are almost not used and easy to drop.
So based on this I concluded that the bridge drivers were used
in a way so we only would need to implement the atomic variants
of the functions.
That said I did not consider .atomic_duplicate_state(),
.atomic_destroy_state(), or .atomic_reset().
From a quick look only cadence/cdns-mhdp8546 subclass
drm_bridge_state and I wonder if the right thing to do would be to
implement fallback to the helpers if the bridge driver do not set
any of the .atomic_duplicate_state(), .atomic_destroy_state(), or .atomic_reset().
That would drop the following from a few bridges:
.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
.atomic_reset = drm_atomic_helper_bridge_reset,
And new bridges (or bridges we convert to use the atomic operations)
would not have to specify them.
I would prefer implementing the fallback - rather than adding the above
to this driver.
Sam
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next prev parent reply other threads:[~2021-10-22 16:54 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-20 18:18 PATCH [v2 0/7] drm/bridge: Drop deprecated functions Sam Ravnborg
2021-10-20 18:18 ` [PATCH v2 1/7] drm/bridge: ps8640: Use atomic variants of drm_bridge_funcs Sam Ravnborg
2021-10-22 14:15 ` Laurent Pinchart
2021-10-22 16:53 ` Sam Ravnborg [this message]
2021-10-22 17:13 ` Sam Ravnborg
2021-10-22 18:42 ` Laurent Pinchart
2021-10-22 19:32 ` Sam Ravnborg
2021-10-22 19:46 ` Laurent Pinchart
2021-10-20 18:18 ` [PATCH v2 2/7] drm/bridge: Drop unused drm_bridge_chain functions Sam Ravnborg
2021-10-20 18:18 ` [PATCH v2 3/7] drm/bridge: Add drm_atomic_get_new_crtc_for_bridge() helper Sam Ravnborg
2021-10-22 11:03 ` Maxime Ripard
2021-10-22 19:33 ` Sam Ravnborg
2021-10-20 18:18 ` [PATCH v2 4/7] drm/bridge: lontium-lt9611: Use atomic variants of drm_bridge_funcs Sam Ravnborg
2021-10-20 18:18 ` [PATCH v2 5/7] drm/mediatek: Drop chain_mode_fixup call in mode_valid() Sam Ravnborg
2021-10-20 18:19 ` [PATCH v2 6/7] drm/bridge: Drop drm_bridge_chain_mode_fixup Sam Ravnborg
2021-10-20 18:19 ` [PATCH v2 7/7] drm/todo: Add bridge related todo items Sam Ravnborg
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