Move the bridge pre_enable call before crtc enable, and the bridge
post_disable call after the crtc disable.
The sequence of enable after this patch will look like:
bridge[n]_pre_enable
...
bridge[1]_pre_enable
crtc_enable
encoder_enable
bridge[1]_enable
...
bridge[n]_enable
And, the disable sequence for the display pipeline will look like:
bridge[n]_disable
...
bridge[1]_disable
encoder_disable
crtc_disable
bridge[1]_post_disable
...
bridge[n]_post_disable
The definition of bridge pre_enable hook says that,
"The display pipe (i.e. clocks and timing signals) feeding this bridge
will not yet be running when this callback is called".
Since CRTC is also a source feeding the bridge, it should not be enabled
before the bridges in the pipeline are pre_enabled. Fix that by
re-ordering the sequence of bridge pre_enable and bridge post_disable.
While at it, update the drm bridge API documentation as well.
Acked-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Tested-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
Signed-off-by: Aradhya Bhatia <aradhya.bhatia@linux.dev>
Tested-by: Devarsh Thakkar <devarsht@ti.com>
Link: https://lore.kernel.org/r/20250605171524.27222-4-aradhya.bhatia@linux.dev
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Bridges obtained via devm_drm_bridge_alloc(dev, ...) will be put when the
requesting device (@dev) is removed.
However drivers which obtained them may need to put the obtained reference
explicitly. One such case is if they bind the devm removal action to a
different device than the one implemented by the driver itself and which
might be removed at a different time, such as bridge/panel.c.
Add devm_drm_put_bridge() to manually release a devm-obtained bridge in
such cases.
This function is considered only a temporary workaround until the panel
bridge is reworked and should be removed afterwards.
Acked-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/20250509-drm-bridge-convert-to-alloc-api-v3-20-b8bc1f16d7aa@bootlin.com
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
DRM bridges are currently considered as a fixed element of a DRM card, and
thus their lifetime is assumed to extend for as long as the card
exists. New use cases, such as hot-pluggable hardware with video bridges,
require DRM bridges to be added to and removed from a DRM card without
tearing the card down. This is possible for connectors already (used by DP
MST), it is now needed for DRM bridges as well.
As a first preliminary step, make bridges reference-counted to allow a
struct drm_bridge (along with the private driver structure embedding it) to
stay allocated even after the driver has been removed, until the last
reference is put.
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20250326-drm-bridge-refcount-v9-2-5e0661fe1f84@bootlin.com
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
Add a macro to allocate and initialize a DRM bridge embedded within a
private driver struct.
Compared to current practice, which is based on [devm_]kzalloc() allocation
followed by open-coded initialization of fields, this allows to have a
common and explicit API to allocate and initialize DRM bridges.
Besides being useful to consolidate bridge driver code, this is a
fundamental step in preparation for adding dynamic lifetime to bridges
based on refcount.
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250326-drm-bridge-refcount-v9-1-5e0661fe1f84@bootlin.com
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
The drm_bridge structure contains an encoder pointer that is widely used
by bridge drivers. This pattern is largely documented as deprecated in
other KMS entities for atomic drivers.
However, one of the main use of that pointer is done in attach to just
call drm_bridge_attach on the next bridge to add it to the bridge list.
While this dereferences the bridge->encoder pointer, it's effectively
the same encoder the bridge was being attached to.
We can make it more explicit by adding the encoder the bridge is
attached to to the list of attach parameters. This also removes the need
to dereference bridge->encoder in most drivers.
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250313-bridge-connector-v6-1-511c54a604fb@kernel.org
Signed-off-by: Maxime Ripard <mripard@kernel.org>
In order to let bridge chains implement HDMI connector infrastructure,
add necessary glue code to the drm_bridge_connector. In case there is a
bridge that sets DRM_BRIDGE_OP_HDMI, drm_bridge_connector will register
itself as a HDMI connector and provide proxy drm_connector_hdmi_funcs
implementation.
Note, to simplify implementation, there can be only one bridge in a
chain that sets DRM_BRIDGE_OP_HDMI. Setting more than one is considered
an error. This limitation can be lifted later, if the need arises.
Acked-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240607-bridge-hdmi-connector-v5-3-ab384e6021af@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Instead of having a single file with all bridge chains, list bridges
under a corresponding per-encoder debugfs directory.
While we are at it, also slightly improve the formatting of the bridge
data: split a single line entry into multiple lines, include the symbol
name of the bridge funcs and add the textual representation of the
bridge ops.
Example of the listing:
$ cat /sys/kernel/debug/dri/0/encoder-0/bridges
bridge[0]: dsi_mgr_bridge_funcs
type: [0] Unknown
ops: [0]
bridge[1]: lt9611uxc_bridge_funcs
type: [11] HDMI-A
OF: /soc@0/geniqup@9c0000/i2c@994000/hdmi-bridge@2b:lontium,lt9611uxc
ops: [7] detect edid hpd
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231203115315.1306124-3-dmitry.baryshkov@linaro.org
Instead of the per minor directories only create a single debugfs
directory for the whole device directly when the device is initialized.
For DRM devices each minor gets a symlink to the per device directory
for now until we can be sure that this isn't useful any more in any way.
Accel devices create only the per device directory and also drops the mid
layer callback to create driver specific files.
v2: cleanup accel component as well
v3: fix typo when debugfs is disabled
v4: call drm_debugfs_dev_fini() during release as well,
some kerneldoc typos fixed
v5: rebased and one more kerneldoc fix
Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230829110115.3442-4-christian.koenig@amd.com
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
DRM bridges are not visible to the userspace and it may not be
immediately clear if the chain is somehow constructed incorrectly. I
have had two separate instances of a bridge driver failing to do a
drm_bridge_attach() call, resulting in the bridge connector not being
part of the chain. In some situations this doesn't seem to cause issues,
but it will if DRM_BRIDGE_ATTACH_NO_CONNECTOR flag is used.
Add a debugfs file to print the bridge chains. For me, on this TI AM62
based platform, I get the following output:
encoder[39]
bridge[0] type: 0, ops: 0x0
bridge[1] type: 0, ops: 0x0, OF: /bus@f0000/i2c@20000000/dsi@e:toshiba,tc358778
bridge[2] type: 0, ops: 0x3, OF: /bus@f0000/i2c@20010000/hdmi@48:lontium,lt8912b
bridge[3] type: 11, ops: 0x7, OF: /hdmi-connector:hdmi-connector
Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Acked-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230802-drm-bridge-chain-debugfs-v4-1-7e3ae3d137c0@ideasonboard.com
DSI sink devices typically want the DSI host powered up and configured
before they are powered up. pre_enable is the place this would normally
happen, but they are called in reverse order from panel/connector towards
the encoder, which is the "wrong" order.
Add a new flag pre_enable_prev_first that any bridge can set
to swap the order of pre_enable (and post_disable) for that and the
immediately previous bridge.
Should the immediately previous bridge also set the
pre_enable_prev_first flag, the previous bridge to that will be called
before either of those which requested pre_enable_prev_first.
eg:
- Panel
- Bridge 1
- Bridge 2 pre_enable_prev_first
- Bridge 3
- Bridge 4 pre_enable_prev_first
- Bridge 5 pre_enable_prev_first
- Bridge 6
- Encoder
Would result in pre_enable's being called as Panel, Bridge 1, Bridge 3,
Bridge 2, Bridge 6, Bridge 5, Bridge 4, Encoder.
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Tested-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Reviewed-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Link: https://lore.kernel.org/r/20221205173328.1395350-5-dave.stevenson@raspberrypi.com
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Panel orientation property should be set before drm_dev_register().
Some drm driver calls drm_dev_register() in .bind(). However, most
panels sets orientation property relatively late, mostly in .get_modes()
callback, since this is when they are able to get the connector and
binds the orientation property to it, though the value should be known
when the panel is probed.
In drm_bridge_connector_init(), if a bridge is a panel bridge, use it to
set the connector's panel orientation property.
Suggested-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
[dianders: fixed space vs. tab indentation]
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220609072722.3488207-9-hsinyi@chromium.org
We'd like panels to be able to add things to debugfs underneath the
connector's directory. Let's plumb it through. A panel will be able to
put things in a "panel" directory under the connector's
directory. Note that debugfs is not ABI and so it's always possible
that the location that the panel gets for its debugfs could change in
the future.
NOTE: this currently only works if you're using a modern
architecture. Specifically the plumbing relies on _both_
drm_bridge_connector and drm_panel_bridge. If you're not using one or
both of these things then things won't be plumbed through.
As a side effect of this change, drm_bridges can also get callbacks to
put stuff underneath the connector's debugfs directory. At the moment
all bridges in the chain have their debugfs_init() called with the
connector's root directory.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220204161245.v2.2.Ib0bd5346135cbb0b63006b69b61d4c8af6484740@changeid
MSM is one of the few drivers which won't even compile
test on !ARM platforms.
Looking into this a bit more it turned out that there is
actually not that much missing to at least let the driver
compile on x86 as well.
So this patch replaces the use of phys_to_page() with the
open coded version and provides a dummy for of_drm_find_bridge().
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210924071759.22659-2-christian.koenig@amd.com
Display drivers so far need to have a lot of boilerplate to first
retrieve either the panel or bridge that they are connected to using
drm_of_find_panel_or_bridge(), and then either deal with each with ad-hoc
functions or create a drm panel bridge through drm_panel_bridge_add.
In order to reduce the boilerplate and hopefully create a path of least
resistance towards using the DRM panel bridge layer, let's create the
function devm_drm_of_get_bridge() to reduce that boilerplate.
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210910130941.1740182-2-maxime@cerno.tech
When validating a mode, bridges may need to do so in the context of a
display, as specified by drm_display_info. An example is the meson
dw-hdmi bridge that needs to consider the YUV 4:2:0 output format to
perform clock calculations.
Bridges that need the display info currently retrieve it from the
drm_connector created by the bridge. This gets in the way of moving
connector creation out of bridge drivers. To make this possible, pass
the drm_display_info to drm_bridge_funcs .mode_valid().
Changes to the bridge drivers have been performed with the following
coccinelle semantic patch and have been compile-tested.
@ rule1 @
identifier funcs;
identifier fn;
@@
struct drm_bridge_funcs funcs = {
...,
.mode_valid = fn
};
@ depends on rule1 @
identifier rule1.fn;
identifier bridge;
identifier mode;
@@
enum drm_mode_status fn(
struct drm_bridge *bridge,
+ const struct drm_display_info *info,
const struct drm_display_mode *mode
)
{
...
}
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Guido Günther <agx@sigxcpu.org> # for the nwl-dsi part:
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200526011505.31884-11-laurent.pinchart+renesas@ideasonboard.com
