[PATCH v3 00/22] drm: convert all bridges to devm_drm_bridge_alloc()

[PATCH v3 00/22] drm: convert all bridges to devm_drm_bridge_alloc()

[Luca Ceresoli]

devm_drm_bridge_alloc() [0] is the new API to allocate and initialize a DRM
bridge, and the only one supported from now on. It is the first milestone
towards removal of bridges from a still existing DRM pipeline without
use-after-free.

The steps in the grand plan [1] are:

 1. ➜ add refcounting to DRM bridges (struct drm_bridge)
 2. handle gracefully atomic updates during bridge removal
 3. avoid DSI host drivers to have dangling pointers to DSI devices
 4. finish the hotplug bridge work, removing the "always-disconnected"
    connector, moving code to the core and potentially removing the
    hotplug-bridge itself (this needs to be clarified as points 1-3 are
    developed)

This series is part of step 1 of the grand plan.

Current tasks in step 1 of the grand plan:

 A. ✔ add new alloc API and refcounting -> (now in drm-misc-next)
 B. ➜ convert all bridge drivers to new API (this series)
 C. … documentation, kunit tests (v1 under discussion)
 D. after (B), add get/put to drm_bridge_add/remove() + attach/detech()
 E. after (B), convert accessors; this is a large work and can be done
    in chunks
 F. debugfs improvements

More info about this series in the v2 cover [2].

Luca

[0] https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/0cc6aadd7fc1e629b715ea3d1ba537ef2da95eec
[1] https://lore.kernel.org/lkml/20250206-hotplug-drm-bridge-v6-0-9d6f2c9c3058@bootlin.com/t/#u
[2] https://lore.kernel.org/lkml/20250424-drm-bridge-convert-to-alloc-api-v2-0-8f91a404d86b@bootlin.com/

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
Changes in v3:
- Fixed issues reported for some patches
- Added review tags
- Removed patches that have been applied
- Added revert for the exynos patch, applied by mistake
- Update cover with grand plan info and trim some of it
- Updated bouncing e-mail address in Cc list
- Link to v2: https://lore.kernel.org/lkml/20250424-drm-bridge-convert-to-alloc-api-v2-0-8f91a404d86b@bootlin.com/

Changes in v2:
- Improved cover letter with link to commit adding devm_drm_bridge_alloc()
- add review tags
- fix bugs in zynqmp, vc4 patches
- fix patch 1 error code checking
- Link to v1: https://lore.kernel.org/r/20250407-drm-bridge-convert-to-alloc-api-v1-0-42113ff8d9c0@bootlin.com

---
Luca Ceresoli (22):
      Revert "drm/exynos: mic: convert to devm_drm_bridge_alloc() API"
      drm: convert many bridge drivers from devm_kzalloc() to devm_drm_bridge_alloc() API
      drm/bridge: anx7625: convert to devm_drm_bridge_alloc() API
      drm/bridge: cdns-dsi: convert to devm_drm_bridge_alloc() API
      drm/bridge: megachips-stdpxxxx-ge-b850v3-fw: convert to devm_drm_bridge_alloc() API
      drm/bridge: nxp-ptn3460: convert to devm_drm_bridge_alloc() API
      drm/bridge: sii902x: convert to devm_drm_bridge_alloc() API
      drm/omap: dss: dpi: convert to devm_drm_bridge_alloc() API
      drm/omap: dss: dsi: convert to devm_drm_bridge_alloc() API
      drm/omap: dss: hdmi4: convert to devm_drm_bridge_alloc() API
      drm/omap: dss: hdmi5: convert to devm_drm_bridge_alloc() API
      drm/omap: dss: sdi: convert to devm_drm_bridge_alloc() API
      drm/omap: dss: venc: convert to devm_drm_bridge_alloc() API
      drm/rcar-du: dsi: convert to devm_drm_bridge_alloc() API
      drm/bridge: stm_lvds: convert to devm_drm_bridge_alloc() API
      drm/sti: dvo: convert to devm_drm_bridge_alloc() API
      drm: zynqmp_dp: convert to devm_drm_bridge_alloc() API
      drm/bridge: imx8qxp-pixel-combiner: convert to devm_drm_bridge_alloc() API
      drm/bridge: tc358767: convert to devm_drm_bridge_alloc() API
      drm/bridge: add devm_drm_put_bridge()
      drm/bridge: panel: convert to devm_drm_bridge_alloc() API
      drm/todo: add entry to remove devm_drm_put_bridge()

 Documentation/gpu/todo.rst                         | 15 ++++++
 drivers/gpu/drm/adp/adp-mipi.c                     |  8 ++--
 drivers/gpu/drm/bridge/adv7511/adv7511_drv.c       |  8 ++--
 drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c |  9 ++--
 drivers/gpu/drm/bridge/analogix/anx7625.c          |  7 ++-
 drivers/gpu/drm/bridge/aux-bridge.c                |  8 ++--
 drivers/gpu/drm/bridge/aux-hpd-bridge.c            |  9 ++--
 drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c     |  8 ++--
 .../gpu/drm/bridge/cadence/cdns-mhdp8546-core.c    |  8 ++--
 drivers/gpu/drm/bridge/chipone-icn6211.c           |  8 ++--
 drivers/gpu/drm/bridge/chrontel-ch7033.c           |  8 ++--
 drivers/gpu/drm/bridge/cros-ec-anx7688.c           |  8 ++--
 drivers/gpu/drm/bridge/fsl-ldb.c                   |  7 ++-
 drivers/gpu/drm/bridge/imx/imx-legacy-bridge.c     |  8 ++--
 drivers/gpu/drm/bridge/imx/imx8mp-hdmi-pvi.c       |  8 ++--
 .../gpu/drm/bridge/imx/imx8qxp-pixel-combiner.c    | 27 ++++++-----
 drivers/gpu/drm/bridge/imx/imx8qxp-pixel-link.c    |  8 ++--
 drivers/gpu/drm/bridge/imx/imx8qxp-pxl2dpi.c       |  8 ++--
 drivers/gpu/drm/bridge/ite-it6263.c                |  8 ++--
 drivers/gpu/drm/bridge/ite-it6505.c                |  8 ++--
 drivers/gpu/drm/bridge/ite-it66121.c               |  8 ++--
 drivers/gpu/drm/bridge/lontium-lt8912b.c           |  8 ++--
 drivers/gpu/drm/bridge/lontium-lt9211.c            |  7 ++-
 drivers/gpu/drm/bridge/lontium-lt9611.c            |  8 ++--
 drivers/gpu/drm/bridge/lvds-codec.c                |  9 ++--
 .../drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c   | 11 ++---
 drivers/gpu/drm/bridge/microchip-lvds.c            |  8 ++--
 drivers/gpu/drm/bridge/nwl-dsi.c                   |  8 ++--
 drivers/gpu/drm/bridge/nxp-ptn3460.c               |  9 ++--
 drivers/gpu/drm/bridge/panel.c                     | 12 ++---
 drivers/gpu/drm/bridge/parade-ps8622.c             |  8 ++--
 drivers/gpu/drm/bridge/parade-ps8640.c             |  8 ++--
 drivers/gpu/drm/bridge/sii902x.c                   |  7 ++-
 drivers/gpu/drm/bridge/sii9234.c                   |  8 ++--
 drivers/gpu/drm/bridge/sil-sii8620.c               |  8 ++--
 drivers/gpu/drm/bridge/simple-bridge.c             |  8 ++--
 drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c       |  8 ++--
 drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c      |  8 ++--
 drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi2.c     |  8 ++--
 drivers/gpu/drm/bridge/tc358762.c                  |  8 ++--
 drivers/gpu/drm/bridge/tc358764.c                  |  8 ++--
 drivers/gpu/drm/bridge/tc358767.c                  | 56 +++++++++++++++-------
 drivers/gpu/drm/bridge/tc358768.c                  |  8 ++--
 drivers/gpu/drm/bridge/tc358775.c                  |  8 ++--
 drivers/gpu/drm/bridge/thc63lvd1024.c              |  8 ++--
 drivers/gpu/drm/bridge/ti-dlpc3433.c               |  8 ++--
 drivers/gpu/drm/bridge/ti-tdp158.c                 |  8 ++--
 drivers/gpu/drm/bridge/ti-tfp410.c                 |  8 ++--
 drivers/gpu/drm/bridge/ti-tpd12s015.c              |  8 ++--
 drivers/gpu/drm/drm_bridge.c                       | 17 +++++++
 drivers/gpu/drm/exynos/exynos_drm_mic.c            |  7 +--
 drivers/gpu/drm/mediatek/mtk_dp.c                  |  8 ++--
 drivers/gpu/drm/mediatek/mtk_dpi.c                 |  8 ++--
 drivers/gpu/drm/mediatek/mtk_dsi.c                 |  8 ++--
 drivers/gpu/drm/mediatek/mtk_hdmi.c                |  8 ++--
 drivers/gpu/drm/meson/meson_encoder_cvbs.c         | 10 ++--
 drivers/gpu/drm/meson/meson_encoder_dsi.c          | 10 ++--
 drivers/gpu/drm/meson/meson_encoder_hdmi.c         | 10 ++--
 drivers/gpu/drm/omapdrm/dss/dpi.c                  |  7 ++-
 drivers/gpu/drm/omapdrm/dss/dsi.c                  |  7 ++-
 drivers/gpu/drm/omapdrm/dss/hdmi4.c                | 26 ++++------
 drivers/gpu/drm/omapdrm/dss/hdmi5.c                | 26 ++++------
 drivers/gpu/drm/omapdrm/dss/sdi.c                  | 25 ++++------
 drivers/gpu/drm/omapdrm/dss/venc.c                 | 23 ++++-----
 drivers/gpu/drm/renesas/rcar-du/rcar_lvds.c        |  8 ++--
 drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c    |  8 ++--
 drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c     |  8 ++--
 drivers/gpu/drm/sti/sti_dvo.c                      | 29 +++++------
 drivers/gpu/drm/stm/lvds.c                         |  7 ++-
 drivers/gpu/drm/xlnx/zynqmp_dp.c                   | 31 +++++-------
 drivers/gpu/drm/xlnx/zynqmp_dpsub.c                |  1 -
 include/drm/drm_bridge.h                           |  4 ++
 72 files changed, 390 insertions(+), 379 deletions(-)
---
base-commit: 94c60d3c1079fc044e356a78ffc68ca7b0603039
change-id: 20250404-drm-bridge-convert-to-alloc-api-614becf62294

Best regards,
-- 
Luca Ceresoli <luca.ceresoli@bootlin.com>

[PATCH v3 22/22] drm/todo: add entry to remove devm_drm_put_bridge()

[Luca Ceresoli]

devm_drm_put_bridge() is a temporary workaround waiting for the panel
bridge lifetime rework. Add a TODO entry to not forget it must be removed
after such rework.

Suggested-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

---

To: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org

This patch was added in v3
---
 Documentation/gpu/todo.rst | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
index c57777a24e03d91b1ffe04365f7356f2d938befd..be8637da3fe950ddcb65cdcf626bc4b4e6b0fa26 100644
--- a/Documentation/gpu/todo.rst
+++ b/Documentation/gpu/todo.rst
@@ -515,6 +515,21 @@ Contact: Douglas Anderson <dianders@chromium.org>
 
 Level: Starter
 
+Remove devm_drm_put_bridge()
+----------------------------
+
+Due to how the panel bridge handles the drm_bridge object lifetime, special
+care must be taken to dispose of the drm_bridge object when the
+panel_bridge is removed. This is currently managed using
+devm_drm_put_bridge(), but that is an unsafe, temporary workaround. To fix
+that, the DRM panel lifetime needs to be reworked. After the rework is
+done, remove devm_drm_put_bridge() and the TODO in
+drm_panel_bridge_remove().
+
+Contact: Maxime Ripard <mripard@kernel.org>,
+         Luca Ceresoli <luca.ceresoli@bootlin.com>
+
+Level: Intermediate
 
 Core refactorings
 =================

-- 
2.49.0

Re: [PATCH v3 22/22] drm/todo: add entry to remove devm_drm_put_bridge()

[Maxime Ripard]

On Fri, 9 May 2025 15:53:48 +0200, Luca Ceresoli wrote:
> devm_drm_put_bridge() is a temporary workaround waiting for the panel
> bridge lifetime rework. Add a TODO entry to not forget it must be removed
> after such rework.
> 
> Suggested-by: Maxime Ripard <mripard@kernel.org>
> 
> [ ... ]

Acked-by: Maxime Ripard <mripard@kernel.org>

Thanks!
Maxime

Re: [PATCH v3 00/22] drm: convert all bridges to devm_drm_bridge_alloc()

[Luca Ceresoli]

Hello Maxime, Shawn, Liu, all,

On Fri, 09 May 2025 15:53:26 +0200
Luca Ceresoli <luca.ceresoli@bootlin.com> wrote:

> devm_drm_bridge_alloc() [0] is the new API to allocate and initialize a DRM
> bridge, and the only one supported from now on. It is the first milestone
> towards removal of bridges from a still existing DRM pipeline without
> use-after-free.

I applied on drm-misc-next patches 3-17,20-21 as they match all the
criteria:
 - At least a Acked-by (or R-by maintainers)
 - patch is for drm-misc

Being my very first commits to drm-misc, I tried to be careful, and
double checked all the patches with Louis (thanks!).

Here are the pending questions and plan for the remaining patches.

>       Revert "drm/exynos: mic: convert to devm_drm_bridge_alloc() API"

This reverts the commit applied my mistake:
https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/91c5c7b5bb2dd09b43b025bce6d790d3c79f4518

Neither the  original patch nor the revert has been reviewed/acked.

As the commit was a mistake, I'm applying the revert by the end of this
week (i.e. on Friday) unless there are better instructions.

>       drm: convert many bridge drivers from devm_kzalloc() to devm_drm_bridge_alloc() API

This patch affects multiple drivers. Running get_maintainers.pl
points at Shawn Guo's repository. After reviewing the MAINTAINERS file,
this looks like due to the 'N:' line in:

ARM/FREESCALE IMX / MXC ARM ARCHITECTURE
M:	Shawn Guo <shawnguo@kernel.org>
M:	Sascha Hauer <s.hauer@pengutronix.de>
R:	Pengutronix Kernel Team <kernel@pengutronix.de>
...
T:	git git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux.git
N:	imx
...

(https://gitlab.freedesktop.org/drm/misc/kernel/-/blob/drm-misc-next/MAINTAINERS?ref_type=heads#L2511-2528)

Here 'imx' matches the 'drivers/gpu/drm/bridge/imx/imx-legacy-bridge.c'
file that is touched by the patch. That regexp appears overly generic to me.

Shawn, can it be fixed by making it less generic?

If not, can we at least add a band-aid 'X:' entry for
drivers/gpu/drm/bridge/imx?

I think the other matching entry is the one to consider:

DRM DRIVERS FOR FREESCALE IMX BRIDGE
M:	Liu Ying <victor.liu@nxp.com>
L:	dri-devel@lists.freedesktop.org
S:	Maintained
F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-ldb.yaml
F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-pixel-combiner.yaml
F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-pixel-link.yaml
F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-pxl2dpi.yaml
F:	drivers/gpu/drm/bridge/imx/

(https://gitlab.freedesktop.org/drm/misc/kernel/-/blob/drm-misc-next/MAINTAINERS?ref_type=heads#L7940-7948)

However it does not list any trees. I _guess_ drm-misc applies here as
a fallback as well as common sense.

Liu, should this entry have a 'T:' line for drm/misc?

>       drm/bridge: imx8qxp-pixel-combiner: convert to devm_drm_bridge_alloc() API

Not acked/reviewed, some discussion happened. I am resending it in v4,
possibly with updates based on the discussion.

But it has the same issue discussed above, with get_maintiners.pl
pointing at Shawn Guo's tree, so in the future I'm assuming this goes
to drm-misc unless there are news about that.

>       drm/bridge: tc358767: convert to devm_drm_bridge_alloc() API

No feedback, resending in v4.

>       drm/todo: add entry to remove devm_drm_put_bridge()

This involves documentation maintained on another tree. Where should it
be applied? There are two matching entries in MAINTAINERS:

 * DRM DRIVERS -> the drm tree
 * DRM DRIVERS AND MISC GPU PATCHES -> the drm-misc tree

To me it looks like the second is obviously the closest match as we are
dealing with DRM bridges, so I'm applying this as well on Friday unless
there are better instructions.

Best regards,
Luca

-- 
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH v3 00/22] drm: convert all bridges to devm_drm_bridge_alloc()

[Liu Ying]

On 05/21/2025, Luca Ceresoli wrote:
> Hello Maxime, Shawn, Liu, all,
> 
> On Fri, 09 May 2025 15:53:26 +0200
> Luca Ceresoli <luca.ceresoli@bootlin.com> wrote:
> 
>> devm_drm_bridge_alloc() [0] is the new API to allocate and initialize a DRM
>> bridge, and the only one supported from now on. It is the first milestone
>> towards removal of bridges from a still existing DRM pipeline without
>> use-after-free.
> 
> I applied on drm-misc-next patches 3-17,20-21 as they match all the
> criteria:
>  - At least a Acked-by (or R-by maintainers)
>  - patch is for drm-misc
> 
> Being my very first commits to drm-misc, I tried to be careful, and
> double checked all the patches with Louis (thanks!).
> 
> Here are the pending questions and plan for the remaining patches.
> 
>>       Revert "drm/exynos: mic: convert to devm_drm_bridge_alloc() API"
> 
> This reverts the commit applied my mistake:
> https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/91c5c7b5bb2dd09b43b025bce6d790d3c79f4518
> 
> Neither the  original patch nor the revert has been reviewed/acked.
> 
> As the commit was a mistake, I'm applying the revert by the end of this
> week (i.e. on Friday) unless there are better instructions.
> 
>>       drm: convert many bridge drivers from devm_kzalloc() to devm_drm_bridge_alloc() API
> 
> This patch affects multiple drivers. Running get_maintainers.pl
> points at Shawn Guo's repository. After reviewing the MAINTAINERS file,
> this looks like due to the 'N:' line in:
> 
> ARM/FREESCALE IMX / MXC ARM ARCHITECTURE
> M:	Shawn Guo <shawnguo@kernel.org>
> M:	Sascha Hauer <s.hauer@pengutronix.de>
> R:	Pengutronix Kernel Team <kernel@pengutronix.de>
> ...
> T:	git git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux.git
> N:	imx
> ...
> 
> (https://gitlab.freedesktop.org/drm/misc/kernel/-/blob/drm-misc-next/MAINTAINERS?ref_type=heads#L2511-2528)
> 
> Here 'imx' matches the 'drivers/gpu/drm/bridge/imx/imx-legacy-bridge.c'
> file that is touched by the patch. That regexp appears overly generic to me.
> 
> Shawn, can it be fixed by making it less generic?
> 
> If not, can we at least add a band-aid 'X:' entry for
> drivers/gpu/drm/bridge/imx?
> 
> I think the other matching entry is the one to consider:
> 
> DRM DRIVERS FOR FREESCALE IMX BRIDGE
> M:	Liu Ying <victor.liu@nxp.com>
> L:	dri-devel@lists.freedesktop.org
> S:	Maintained
> F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-ldb.yaml
> F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-pixel-combiner.yaml
> F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-pixel-link.yaml
> F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-pxl2dpi.yaml
> F:	drivers/gpu/drm/bridge/imx/
> 
> (https://gitlab.freedesktop.org/drm/misc/kernel/-/blob/drm-misc-next/MAINTAINERS?ref_type=heads#L7940-7948)
> 
> However it does not list any trees. I _guess_ drm-misc applies here as
> a fallback as well as common sense.
> 
> Liu, should this entry have a 'T:' line for drm/misc?

These bridge drivers also don't have a 'T:' line:

DRM DRIVER FOR CHIPONE ICN6211 MIPI-DSI to RGB CONVERTER BRIDGE
DRM DRIVER FOR PARADE PS8640 BRIDGE CHIP
DRM DRIVER FOR TI DLPC3433 MIPI DSI TO DMD BRIDGE
DRM DRIVER FOR TI SN65DSI86 BRIDGE CHIP
LONTIUM LT8912B MIPI TO HDMI BRIDGE
MEGACHIPS STDPXXXX-GE-B850V3-FW LVDS/DP++ BRIDGES
MICROCHIP SAM9x7-COMPATIBLE LVDS CONTROLLER

I think that they fallback to drm-misc since "DRM DRIVERS FOR BRIDGE CHIPS"
covers them.  I don't have strong opinion on adding a "T" line to them, at
least to "DRM DRIVERS FOR FREESCALE IMX BRIDGE".  Anyway, it would be good
to know comments from maintainers for "DRM DRIVERS FOR BRIDGE CHIPS" and
"DRM DRIVERS".

> 
>>       drm/bridge: imx8qxp-pixel-combiner: convert to devm_drm_bridge_alloc() API
> 
> Not acked/reviewed, some discussion happened. I am resending it in v4,
> possibly with updates based on the discussion.

I still think the main structures in imx8qxp-pixel-combiner.c and imx*-ldb.c
should have the same lifetime with the allocated bridges.  I added a new
comment on this driver in v2 just now.

> 
> But it has the same issue discussed above, with get_maintiners.pl
> pointing at Shawn Guo's tree, so in the future I'm assuming this goes
> to drm-misc unless there are news about that.
> 
>>       drm/bridge: tc358767: convert to devm_drm_bridge_alloc() API
> 
> No feedback, resending in v4.
> 
>>       drm/todo: add entry to remove devm_drm_put_bridge()
> 
> This involves documentation maintained on another tree. Where should it
> be applied? There are two matching entries in MAINTAINERS:
> 
>  * DRM DRIVERS -> the drm tree
>  * DRM DRIVERS AND MISC GPU PATCHES -> the drm-misc tree
> 
> To me it looks like the second is obviously the closest match as we are
> dealing with DRM bridges, so I'm applying this as well on Friday unless
> there are better instructions.
> 
> Best regards,
> Luca
> 

-- 
Regards,
Liu Ying

Re: [PATCH v3 00/22] drm: convert all bridges to devm_drm_bridge_alloc()

[Luca Ceresoli]

Hello Liu,

On Thu, 22 May 2025 11:20:17 +0800
Liu Ying <victor.liu@nxp.com> wrote:

> > If not, can we at least add a band-aid 'X:' entry for
> > drivers/gpu/drm/bridge/imx?
> > 
> > I think the other matching entry is the one to consider:
> > 
> > DRM DRIVERS FOR FREESCALE IMX BRIDGE
> > M:	Liu Ying <victor.liu@nxp.com>
> > L:	dri-devel@lists.freedesktop.org
> > S:	Maintained
> > F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-ldb.yaml
> > F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-pixel-combiner.yaml
> > F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-pixel-link.yaml
> > F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-pxl2dpi.yaml
> > F:	drivers/gpu/drm/bridge/imx/
> > 
> > (https://gitlab.freedesktop.org/drm/misc/kernel/-/blob/drm-misc-next/MAINTAINERS?ref_type=heads#L7940-7948)
> > 
> > However it does not list any trees. I _guess_ drm-misc applies here as
> > a fallback as well as common sense.
> > 
> > Liu, should this entry have a 'T:' line for drm/misc?  
> 
> These bridge drivers also don't have a 'T:' line:
> 
> DRM DRIVER FOR CHIPONE ICN6211 MIPI-DSI to RGB CONVERTER BRIDGE
> DRM DRIVER FOR PARADE PS8640 BRIDGE CHIP
> DRM DRIVER FOR TI DLPC3433 MIPI DSI TO DMD BRIDGE
> DRM DRIVER FOR TI SN65DSI86 BRIDGE CHIP
> LONTIUM LT8912B MIPI TO HDMI BRIDGE
> MEGACHIPS STDPXXXX-GE-B850V3-FW LVDS/DP++ BRIDGES
> MICROCHIP SAM9x7-COMPATIBLE LVDS CONTROLLER
> 
> I think that they fallback to drm-misc since "DRM DRIVERS FOR BRIDGE CHIPS"
> covers them.  I don't have strong opinion on adding a "T" line to them, at
> least to "DRM DRIVERS FOR FREESCALE IMX BRIDGE".  Anyway, it would be good
> to know comments from maintainers for "DRM DRIVERS FOR BRIDGE CHIPS" and
> "DRM DRIVERS".

I agree the fallback seems OK for this MAINTAINERS entry.

The other entry (ARM/FREESCALE IMX / MXC ARM ARCHITECTURE) is another
story.

> >>       drm/bridge: imx8qxp-pixel-combiner: convert to devm_drm_bridge_alloc() API  
> > 
> > Not acked/reviewed, some discussion happened. I am resending it in v4,
> > possibly with updates based on the discussion.  
> 
> I still think the main structures in imx8qxp-pixel-combiner.c and imx*-ldb.c
> should have the same lifetime with the allocated bridges.  I added a new
> comment on this driver in v2 just now.

Thanks, let's continue the conversation there.

Luca

-- 
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH v3 00/22] drm: convert all bridges to devm_drm_bridge_alloc()

[Maxime Ripard]

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On Wed, May 21, 2025 at 04:22:16PM +0200, Luca Ceresoli wrote:
> Hello Maxime, Shawn, Liu, all,
> 
> On Fri, 09 May 2025 15:53:26 +0200
> Luca Ceresoli <luca.ceresoli@bootlin.com> wrote:
> 
> > devm_drm_bridge_alloc() [0] is the new API to allocate and initialize a DRM
> > bridge, and the only one supported from now on. It is the first milestone
> > towards removal of bridges from a still existing DRM pipeline without
> > use-after-free.
> 
> I applied on drm-misc-next patches 3-17,20-21 as they match all the
> criteria:
>  - At least a Acked-by (or R-by maintainers)
>  - patch is for drm-misc
> 
> Being my very first commits to drm-misc, I tried to be careful, and
> double checked all the patches with Louis (thanks!).
> 
> Here are the pending questions and plan for the remaining patches.
> 
> >       Revert "drm/exynos: mic: convert to devm_drm_bridge_alloc() API"
> 
> This reverts the commit applied my mistake:
> https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/91c5c7b5bb2dd09b43b025bce6d790d3c79f4518
> 
> Neither the  original patch nor the revert has been reviewed/acked.
> 
> As the commit was a mistake, I'm applying the revert by the end of this
> week (i.e. on Friday) unless there are better instructions.

Given the lack of answers, and that it looks correct to me, just leave
it there. We can always revert later on if things turned out to be
broken.

> >       drm: convert many bridge drivers from devm_kzalloc() to devm_drm_bridge_alloc() API
> 
> This patch affects multiple drivers. Running get_maintainers.pl
> points at Shawn Guo's repository. After reviewing the MAINTAINERS file,
> this looks like due to the 'N:' line in:
> 
> ARM/FREESCALE IMX / MXC ARM ARCHITECTURE
> M:	Shawn Guo <shawnguo@kernel.org>
> M:	Sascha Hauer <s.hauer@pengutronix.de>
> R:	Pengutronix Kernel Team <kernel@pengutronix.de>
> ...
> T:	git git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux.git
> N:	imx
> ...
> 
> (https://gitlab.freedesktop.org/drm/misc/kernel/-/blob/drm-misc-next/MAINTAINERS?ref_type=heads#L2511-2528)
> 
> Here 'imx' matches the 'drivers/gpu/drm/bridge/imx/imx-legacy-bridge.c'
> file that is touched by the patch. That regexp appears overly generic to me.

I agree, or at least, we shouldn't wait for Shawn or Sasha...

> Shawn, can it be fixed by making it less generic?
> 
> If not, can we at least add a band-aid 'X:' entry for
> drivers/gpu/drm/bridge/imx?
> 
> I think the other matching entry is the one to consider:
> 
> DRM DRIVERS FOR FREESCALE IMX BRIDGE
> M:	Liu Ying <victor.liu@nxp.com>
> L:	dri-devel@lists.freedesktop.org
> S:	Maintained
> F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-ldb.yaml
> F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-pixel-combiner.yaml
> F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-pixel-link.yaml
> F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-pxl2dpi.yaml
> F:	drivers/gpu/drm/bridge/imx/
> 
> (https://gitlab.freedesktop.org/drm/misc/kernel/-/blob/drm-misc-next/MAINTAINERS?ref_type=heads#L7940-7948)

... As long as Ying is fine with it, because it does look like they are
the actual maintainer.

> However it does not list any trees. I _guess_ drm-misc applies here as
> a fallback as well as common sense.
> 
> Liu, should this entry have a 'T:' line for drm/misc?
> 
> >       drm/bridge: imx8qxp-pixel-combiner: convert to devm_drm_bridge_alloc() API
> 
> Not acked/reviewed, some discussion happened. I am resending it in v4,
> possibly with updates based on the discussion.
> 
> But it has the same issue discussed above, with get_maintiners.pl
> pointing at Shawn Guo's tree, so in the future I'm assuming this goes
> to drm-misc unless there are news about that.
> 
> >       drm/bridge: tc358767: convert to devm_drm_bridge_alloc() API
> 
> No feedback, resending in v4.
> 
> >       drm/todo: add entry to remove devm_drm_put_bridge()
> 
> This involves documentation maintained on another tree. Where should it
> be applied? There are two matching entries in MAINTAINERS:
> 
>  * DRM DRIVERS -> the drm tree
>  * DRM DRIVERS AND MISC GPU PATCHES -> the drm-misc tree
> 
> To me it looks like the second is obviously the closest match as we are
> dealing with DRM bridges, so I'm applying this as well on Friday unless
> there are better instructions.

Yes, they should be applied to drm-misc.

That being said, putting a two days timeout on *any* email is really
over-the-top. I doubt you reply to any of your mail in such a short
timeframe. We have rules for a reason, I'd expect you to follow them, no
matter how frustrating the lack of answers can be.

Maxime

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Re: [PATCH v3 00/22] drm: convert all bridges to devm_drm_bridge_alloc()

[Maxime Ripard]

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On Thu, May 22, 2025 at 11:20:17AM +0800, Liu Ying wrote:
> >>       drm: convert many bridge drivers from devm_kzalloc() to devm_drm_bridge_alloc() API
> > 
> > This patch affects multiple drivers. Running get_maintainers.pl
> > points at Shawn Guo's repository. After reviewing the MAINTAINERS file,
> > this looks like due to the 'N:' line in:
> > 
> > ARM/FREESCALE IMX / MXC ARM ARCHITECTURE
> > M:	Shawn Guo <shawnguo@kernel.org>
> > M:	Sascha Hauer <s.hauer@pengutronix.de>
> > R:	Pengutronix Kernel Team <kernel@pengutronix.de>
> > ...
> > T:	git git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux.git
> > N:	imx
> > ...
> > 
> > (https://gitlab.freedesktop.org/drm/misc/kernel/-/blob/drm-misc-next/MAINTAINERS?ref_type=heads#L2511-2528)
> > 
> > Here 'imx' matches the 'drivers/gpu/drm/bridge/imx/imx-legacy-bridge.c'
> > file that is touched by the patch. That regexp appears overly generic to me.
> > 
> > Shawn, can it be fixed by making it less generic?
> > 
> > If not, can we at least add a band-aid 'X:' entry for
> > drivers/gpu/drm/bridge/imx?
> > 
> > I think the other matching entry is the one to consider:
> > 
> > DRM DRIVERS FOR FREESCALE IMX BRIDGE
> > M:	Liu Ying <victor.liu@nxp.com>
> > L:	dri-devel@lists.freedesktop.org
> > S:	Maintained
> > F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-ldb.yaml
> > F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-pixel-combiner.yaml
> > F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-pixel-link.yaml
> > F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-pxl2dpi.yaml
> > F:	drivers/gpu/drm/bridge/imx/
> > 
> > (https://gitlab.freedesktop.org/drm/misc/kernel/-/blob/drm-misc-next/MAINTAINERS?ref_type=heads#L7940-7948)
> > 
> > However it does not list any trees. I _guess_ drm-misc applies here as
> > a fallback as well as common sense.
> > 
> > Liu, should this entry have a 'T:' line for drm/misc?
> 
> These bridge drivers also don't have a 'T:' line:
> 
> DRM DRIVER FOR CHIPONE ICN6211 MIPI-DSI to RGB CONVERTER BRIDGE
> DRM DRIVER FOR PARADE PS8640 BRIDGE CHIP
> DRM DRIVER FOR TI DLPC3433 MIPI DSI TO DMD BRIDGE
> DRM DRIVER FOR TI SN65DSI86 BRIDGE CHIP
> LONTIUM LT8912B MIPI TO HDMI BRIDGE
> MEGACHIPS STDPXXXX-GE-B850V3-FW LVDS/DP++ BRIDGES
> MICROCHIP SAM9x7-COMPATIBLE LVDS CONTROLLER
> 
> I think that they fallback to drm-misc since "DRM DRIVERS FOR BRIDGE CHIPS"
> covers them.  I don't have strong opinion on adding a "T" line to them, at
> least to "DRM DRIVERS FOR FREESCALE IMX BRIDGE".  Anyway, it would be good
> to know comments from maintainers for "DRM DRIVERS FOR BRIDGE CHIPS" and
> "DRM DRIVERS".

That's good enough to me. drivers/gpu/drm/bridge is indeed under the
maintenance of drm-misc and there's no exception afaik.

get_maintainers.pl also properly reports it, so I'm not sure we need to
do anything there.

Maxime

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Re: [PATCH v3 00/22] drm: convert all bridges to devm_drm_bridge_alloc()

[Inki Dae]

Hello Luca Ceresoli,

2025년 5월 21일 (수) 오후 11:23, Luca Ceresoli <luca.ceresoli@bootlin.com>님이 작성:
>
> Hello Maxime, Shawn, Liu, all,
>
> On Fri, 09 May 2025 15:53:26 +0200
> Luca Ceresoli <luca.ceresoli@bootlin.com> wrote:
>
> > devm_drm_bridge_alloc() [0] is the new API to allocate and initialize a DRM
> > bridge, and the only one supported from now on. It is the first milestone
> > towards removal of bridges from a still existing DRM pipeline without
> > use-after-free.
>
> I applied on drm-misc-next patches 3-17,20-21 as they match all the
> criteria:
>  - At least a Acked-by (or R-by maintainers)
>  - patch is for drm-misc
>
> Being my very first commits to drm-misc, I tried to be careful, and
> double checked all the patches with Louis (thanks!).
>
> Here are the pending questions and plan for the remaining patches.
>
> >       Revert "drm/exynos: mic: convert to devm_drm_bridge_alloc() API"
>
> This reverts the commit applied my mistake:
> https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/91c5c7b5bb2dd09b43b025bce6d790d3c79f4518
>
> Neither the  original patch nor the revert has been reviewed/acked.
>
> As the commit was a mistake, I'm applying the revert by the end of this
> week (i.e. on Friday) unless there are better instructions.

Really sorry for late. I was made aware of it later through a
colleague's remark. There is no need to proceed with the revert.
Acked-by : Inki Dae <inki.dae@samsung.com>

Thanks,
Inki Dae


>
> >       drm: convert many bridge drivers from devm_kzalloc() to devm_drm_bridge_alloc() API
>
> This patch affects multiple drivers. Running get_maintainers.pl
> points at Shawn Guo's repository. After reviewing the MAINTAINERS file,
> this looks like due to the 'N:' line in:
>
> ARM/FREESCALE IMX / MXC ARM ARCHITECTURE
> M:      Shawn Guo <shawnguo@kernel.org>
> M:      Sascha Hauer <s.hauer@pengutronix.de>
> R:      Pengutronix Kernel Team <kernel@pengutronix.de>
> ...
> T:      git git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux.git
> N:      imx
> ...
>
> (https://gitlab.freedesktop.org/drm/misc/kernel/-/blob/drm-misc-next/MAINTAINERS?ref_type=heads#L2511-2528)
>
> Here 'imx' matches the 'drivers/gpu/drm/bridge/imx/imx-legacy-bridge.c'
> file that is touched by the patch. That regexp appears overly generic to me.
>
> Shawn, can it be fixed by making it less generic?
>
> If not, can we at least add a band-aid 'X:' entry for
> drivers/gpu/drm/bridge/imx?
>
> I think the other matching entry is the one to consider:
>
> DRM DRIVERS FOR FREESCALE IMX BRIDGE
> M:      Liu Ying <victor.liu@nxp.com>
> L:      dri-devel@lists.freedesktop.org
> S:      Maintained
> F:      Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-ldb.yaml
> F:      Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-pixel-combiner.yaml
> F:      Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-pixel-link.yaml
> F:      Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-pxl2dpi.yaml
> F:      drivers/gpu/drm/bridge/imx/
>
> (https://gitlab.freedesktop.org/drm/misc/kernel/-/blob/drm-misc-next/MAINTAINERS?ref_type=heads#L7940-7948)
>
> However it does not list any trees. I _guess_ drm-misc applies here as
> a fallback as well as common sense.
>
> Liu, should this entry have a 'T:' line for drm/misc?
>
> >       drm/bridge: imx8qxp-pixel-combiner: convert to devm_drm_bridge_alloc() API
>
> Not acked/reviewed, some discussion happened. I am resending it in v4,
> possibly with updates based on the discussion.
>
> But it has the same issue discussed above, with get_maintiners.pl
> pointing at Shawn Guo's tree, so in the future I'm assuming this goes
> to drm-misc unless there are news about that.
>
> >       drm/bridge: tc358767: convert to devm_drm_bridge_alloc() API
>
> No feedback, resending in v4.
>
> >       drm/todo: add entry to remove devm_drm_put_bridge()
>
> This involves documentation maintained on another tree. Where should it
> be applied? There are two matching entries in MAINTAINERS:
>
>  * DRM DRIVERS -> the drm tree
>  * DRM DRIVERS AND MISC GPU PATCHES -> the drm-misc tree
>
> To me it looks like the second is obviously the closest match as we are
> dealing with DRM bridges, so I'm applying this as well on Friday unless
> there are better instructions.
>
> Best regards,
> Luca
>
> --
> Luca Ceresoli, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com
>

Re: [PATCH v3 00/22] drm: convert all bridges to devm_drm_bridge_alloc()

[Luca Ceresoli]

Hi Maxime,

On Thu, 22 May 2025 16:57:30 +0200
Maxime Ripard <mripard@kernel.org> wrote:

[...]

> > As the commit was a mistake, I'm applying the revert by the end of this
> > week (i.e. on Friday) unless there are better instructions.  
> 
> Given the lack of answers, and that it looks correct to me, just leave
> it there. We can always revert later on if things turned out to be
> broken.

OK, I'll leave the commit and drop the revert in v4.

> > >       drm: convert many bridge drivers from devm_kzalloc() to devm_drm_bridge_alloc() API  
> > 
> > This patch affects multiple drivers. Running get_maintainers.pl
> > points at Shawn Guo's repository. After reviewing the MAINTAINERS file,
> > this looks like due to the 'N:' line in:
> > 
> > ARM/FREESCALE IMX / MXC ARM ARCHITECTURE
> > M:	Shawn Guo <shawnguo@kernel.org>
> > M:	Sascha Hauer <s.hauer@pengutronix.de>
> > R:	Pengutronix Kernel Team <kernel@pengutronix.de>
> > ...
> > T:	git git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux.git
> > N:	imx
> > ...
> > 
> > (https://gitlab.freedesktop.org/drm/misc/kernel/-/blob/drm-misc-next/MAINTAINERS?ref_type=heads#L2511-2528)
> > 
> > Here 'imx' matches the 'drivers/gpu/drm/bridge/imx/imx-legacy-bridge.c'
> > file that is touched by the patch. That regexp appears overly generic to me.  
> 
> I agree, or at least, we shouldn't wait for Shawn or Sasha...
> 
> > Shawn, can it be fixed by making it less generic?
> > 
> > If not, can we at least add a band-aid 'X:' entry for
> > drivers/gpu/drm/bridge/imx?
> > 
> > I think the other matching entry is the one to consider:
> > 
> > DRM DRIVERS FOR FREESCALE IMX BRIDGE
> > M:	Liu Ying <victor.liu@nxp.com>
> > L:	dri-devel@lists.freedesktop.org
> > S:	Maintained
> > F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-ldb.yaml
> > F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-pixel-combiner.yaml
> > F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-pixel-link.yaml
> > F:	Documentation/devicetree/bindings/display/bridge/fsl,imx8qxp-pxl2dpi.yaml
> > F:	drivers/gpu/drm/bridge/imx/
> > 
> > (https://gitlab.freedesktop.org/drm/misc/kernel/-/blob/drm-misc-next/MAINTAINERS?ref_type=heads#L7940-7948)  
> 
> ... As long as Ying is fine with it, because it does look like they are
> the actual maintainer.

Ack, thanks for confirming this.

Bottom line, given that large patch has your Acked-by, and given the
shawnguo repo was ruled out, the conclusion is it can apply it to
drm-misc-next.

Having that large patch applied will be relieving me a lot! I think
next time I'm going to split any imilar change in per-driver patches,
even if it is spatch-automated.

> > >       drm/todo: add entry to remove devm_drm_put_bridge()  
> > 
> > This involves documentation maintained on another tree. Where should it
> > be applied? There are two matching entries in MAINTAINERS:
> > 
> >  * DRM DRIVERS -> the drm tree
> >  * DRM DRIVERS AND MISC GPU PATCHES -> the drm-misc tree
> > 
> > To me it looks like the second is obviously the closest match as we are
> > dealing with DRM bridges, so I'm applying this as well on Friday unless
> > there are better instructions.  
> 
> Yes, they should be applied to drm-misc.

OK, will do soon.

> That being said, putting a two days timeout on *any* email is really
> over-the-top. I doubt you reply to any of your mail in such a short
> timeframe. We have rules for a reason, I'd expect you to follow them, no
> matter how frustrating the lack of answers can be.

Apologies if that was too much.

I was indeed nervous about the revert. A patch got applied by mistake
and I believe it should have been reverted very quickly, if need be.
Both Louis and I didn't want to break the process again. So we asked,
but not having answer after 2+ weeks I must admit I got a bit nervous
about it.

Sorry about that and thanks for the feedback about my questions.

Luca

-- 
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH v3 00/22] drm: convert all bridges to devm_drm_bridge_alloc()

[Luca Ceresoli]

Hello Inki,

On Fri, 23 May 2025 00:11:24 +0900
Inki Dae <daeinki@gmail.com> wrote:

> Hello Luca Ceresoli,
> 
> 2025년 5월 21일 (수) 오후 11:23, Luca Ceresoli <luca.ceresoli@bootlin.com>님이 작성:
> >
> > Hello Maxime, Shawn, Liu, all,
> >
> > On Fri, 09 May 2025 15:53:26 +0200
> > Luca Ceresoli <luca.ceresoli@bootlin.com> wrote:
> >  
> > > devm_drm_bridge_alloc() [0] is the new API to allocate and initialize a DRM
> > > bridge, and the only one supported from now on. It is the first milestone
> > > towards removal of bridges from a still existing DRM pipeline without
> > > use-after-free.  
> >
> > I applied on drm-misc-next patches 3-17,20-21 as they match all the
> > criteria:
> >  - At least a Acked-by (or R-by maintainers)
> >  - patch is for drm-misc
> >
> > Being my very first commits to drm-misc, I tried to be careful, and
> > double checked all the patches with Louis (thanks!).
> >
> > Here are the pending questions and plan for the remaining patches.
> >  
> > >       Revert "drm/exynos: mic: convert to devm_drm_bridge_alloc() API"  
> >
> > This reverts the commit applied my mistake:
> > https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/91c5c7b5bb2dd09b43b025bce6d790d3c79f4518
> >
> > Neither the  original patch nor the revert has been reviewed/acked.
> >
> > As the commit was a mistake, I'm applying the revert by the end of this
> > week (i.e. on Friday) unless there are better instructions.  
> 
> Really sorry for late. I was made aware of it later through a
> colleague's remark. There is no need to proceed with the revert.
> Acked-by : Inki Dae <inki.dae@samsung.com>

Thanks for the feedback. As agreed with Maxime and approved by you, I'm
leaving the commit as is, without reverting and reapplying. Your
Acked-by is in the records anyway, so somehow reachable in case of need.

Luca

-- 
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: (subset) [PATCH v3 00/22] drm: convert all bridges to devm_drm_bridge_alloc()

[Luca Ceresoli]

On Fri, 09 May 2025 15:53:26 +0200, Luca Ceresoli wrote:
> devm_drm_bridge_alloc() [0] is the new API to allocate and initialize a DRM
> bridge, and the only one supported from now on. It is the first milestone
> towards removal of bridges from a still existing DRM pipeline without
> use-after-free.
> 
> The steps in the grand plan [1] are:
> 
> [...]

Applied, thanks!

[18/22] drm/bridge: imx8qxp-pixel-combiner: convert to devm_drm_bridge_alloc() API
        commit: 99764593528f9e0ee9509f9e4a4eb21db99d0681

Best regards,
-- 
Luca Ceresoli <luca.ceresoli@bootlin.com>