Re: [PATCH v6 00/16] drm/vkms: Add configfs support

[Harry Wentland <harry.wentland@amd.com>]

On 2025-09-01 08:25, José Expósito wrote:
> Hi everyone,
> 
> This series allow to configure one or more VKMS instances without having
> to reload the driver using configfs.
> 
> The process of configuring a VKMS device is documented in "vkms.rst".
> 
> In addition, I created a CLI tool to easily control VKMS instances from the
> command line: vkmsctl [1].
> 
> The series is structured in 3 blocks:
> 
>    - Patches 1..11: Basic device configuration. For simplicity, I kept the
>      available options as minimal as possible.
> 
>    - Patches 12 and 13: New option to skip the default device creation and to-do
>      cleanup.
> 
>    - Patches 14, 15 and 16: Allow to hot-plug and unplug connectors. This is not
>      part of the minimal set of options, but I included in this series so it can
>      be used as a template/example of how new configurations can be added.
> 
> Finally, the code is thoroughly tested by a collection of IGT tests [2]. The IGT
> series is almost fully reviewed (1 patch is missing) and it is waiting on this
> series to be merged.
> 
> I don't know what is preventing this series to be ACK by a DRM maintainer, but
> please, if there is something missing or that needs to be fixed let me know.
> 
> I CCed the configfs maintainers in case they can give feedback about the design
> of the configfs API or the configfs related code, just in case that is one of
> the complicated points to review by DRM maintainers.
> 

While I'm not a configfs expert these patches look good to me. With the 
two comments about function docs fixed these patches are
Reviewed-by: Harry Wentland <harry.wentland@amd.com>

I went through them manually and also asked both GPT 4.1 and Claude 
Sonnet 4 to review them for correctness against the configfs.rst docs.

Harry

> Best wishes,
> José Expósito
> 
> [1] https://github.com/JoseExposito/vkmsctl
> [2] https://lore.kernel.org/igt-dev/20250807074550.6543-1-jose.exposito89@gmail.com/
> 
> Changes in v6:
> 
>    - No code changes, rebased on top of drm-misc-next
>    - Added Tested-by: Mark Yacoub, who merged the series into the Android tree (thanks!)
>      https://lore.kernel.org/dri-devel/CAC0gqY6ZH8h5aoNh31ck3dP6c3YYtfTRjJ47Obu6xSXSVXm5mA@mail.gmail.com/
>    - Added a link in the cover letter the CLI to configure VKMS: vkmsctl
>    - CCed more people to try to get the series merged
>    - Link to v5: https://lore.kernel.org/dri-devel/20250507135431.53907-1-jose.exposito89@gmail.com/
> 
> Changes in v5:
> 
>    - No code changes, rebased on top of drm-misc-next
>    - Added Reviewed-by tags, thanks Louis!
>    - Link to v4: https://lore.kernel.org/dri-devel/20250407081425.6420-1-jose.exposito89@gmail.com/
> 
> Changes in v4:
> 
>    - No code changes, rebased on top of drm-misc-next
>    - Since Louis and I worked on this together, set him as the author of some of
>      the patches and me as co-developed-by to reflect this joint effort.
>    - Link to v3: https://lore.kernel.org/all/20250307163353.5896-1-jose.exposito89@gmail.com/
> 
> Changes in v3:
> 
>    - Applied review comments by Louis Chauvet: (thanks!!)
>      - Use scoped_guard() instead of guard(mutex)(...)
>      - Fix a use-after-free error in the connector hot-plug code
>    - Rebased on top of drm-misc-next
>    - Link to v2: https://lore.kernel.org/all/20250225175936.7223-1-jose.exposito89@gmail.com/
> 
> Changes in v2:
> 
>    - Applied review comments by Louis Chauvet:
>      - Use guard(mutex)(...) instead of lock/unlock
>      - Return -EBUSY when trying to modify a enabled device
>      - Move the connector hot-plug related patches to the end
>    - Rebased on top of drm-misc-next
>    - Link to v1: https://lore.kernel.org/dri-devel/20250218170808.9507-1-jose.exposito89@gmail.com/T/
> 
> José Expósito (6):
>    drm/vkms: Expose device creation and destruction
>    drm/vkms: Allow to configure the default device creation
>    drm/vkms: Remove completed task from the TODO list
>    drm/vkms: Allow to configure connector status
>    drm/vkms: Allow to update the connector status
>    drm/vkms: Allow to configure connector status via configfs
> 
> Louis Chauvet (10):
>    drm/vkms: Add and remove VKMS instances via configfs
>    drm/vkms: Allow to configure multiple planes via configfs
>    drm/vkms: Allow to configure the plane type via configfs
>    drm/vkms: Allow to configure multiple CRTCs via configfs
>    drm/vkms: Allow to configure CRTC writeback support via configfs
>    drm/vkms: Allow to attach planes and CRTCs via configfs
>    drm/vkms: Allow to configure multiple encoders via configfs
>    drm/vkms: Allow to attach encoders and CRTCs via configfs
>    drm/vkms: Allow to configure multiple connectors via configfs
>    drm/vkms: Allow to attach connectors and encoders via configfs
> 
>   Documentation/gpu/vkms.rst                    | 100 ++-
>   drivers/gpu/drm/vkms/Kconfig                  |   1 +
>   drivers/gpu/drm/vkms/Makefile                 |   3 +-
>   drivers/gpu/drm/vkms/tests/vkms_config_test.c |  24 +
>   drivers/gpu/drm/vkms/vkms_config.c            |   8 +-
>   drivers/gpu/drm/vkms/vkms_config.h            |  26 +
>   drivers/gpu/drm/vkms/vkms_configfs.c          | 833 ++++++++++++++++++
>   drivers/gpu/drm/vkms/vkms_configfs.h          |   8 +
>   drivers/gpu/drm/vkms/vkms_connector.c         |  35 +
>   drivers/gpu/drm/vkms/vkms_connector.h         |   9 +
>   drivers/gpu/drm/vkms/vkms_drv.c               |  18 +-
>   drivers/gpu/drm/vkms/vkms_drv.h               |  20 +
>   12 files changed, 1072 insertions(+), 13 deletions(-)
>   create mode 100644 drivers/gpu/drm/vkms/vkms_configfs.c
>   create mode 100644 drivers/gpu/drm/vkms/vkms_configfs.h
> 
> 
> base-commit: 6b53cf48d9339c75fa51927b0a67d8a6751066bd