Re: [PATCH 00/10] vga_switcheroo, drm: Push fbcon handling into DRM clients

[lyude@redhat.com]

For both nouveau patches:

Reviewed-by: Lyude Paul <lyude@redhat.com>

On Tue, 2026-07-07 at 15:38 +0200, Thomas Zimmermann wrote:
> Vga_switcheroo currently invokes fb_switch_outputs() to inform fbcon
> about switching of the physical outputs among framebuffer devices.
> But
> new DRM clients to not use fbdev/fbcon and might require their own
> vga_switcheroo support. Let's strictly separate them from each other.
> 
> Remove fbdev/fbcon from vga_switcheroo. Introduce a pre_switch
> callback
> for vga_switcheroo clients to do the fbcon update. Allows for
> removing
> all direct interactions between vga_switcheroo and fbdev/fbcon.
> 
> Also replace the existing reprobe hook with post_switch for symetry.
> 
> At the same time, push the fbcon update into DRM's client for fbdev
> emulation. Do this with the new DRM client callback acquire_outputs,
> so that other clients can have their own handling of vga_switcheroo.
> 
> There are only four drivers that support vga_switcheroo: amdgpu,
> radeon, i915 and nouveau. Update each of them with the new callbacks.
> When vga_switcheroo now invokes pre_switch, each DRM driver forwards
> to aquire_outputs and lets the DRM clients handle the new outputs.
> 
> Tested with radeon on a notebook with Radeon HD 4225 and HD 5430.
> 
> Thomas Zimmermann (10):
>   drm/edid: Include <linux/fb.h>
>   drm/client: Add acquire_outputs callback; implement for fbdev
>     emulation
>   vga_switcheroo: Add pre_switch callback to client ops
>   vga_switcheroo: Add post_switch callback to client ops
>   drm/amdgpu: Implement struct vga_switcheroo_client_ops.pre_switch
>   drm/i915: Implement vga_switcheroo_client_ops.pre_switch
>   drm/nouveau: Implement vga_switcheroo_client_ops.pre_switch
>   drm/nouveau: Implement vga_switcheroo_client_ops.post_switch
>   drm/radeon: Implement struct vga_switcheroo_client_ops.pre_switch
>   vga-switcheroo: Remove unused interfaces
> 
>  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c |  9 ++++-
>  drivers/gpu/drm/clients/drm_fbdev_client.c | 23 ++++++++----
>  drivers/gpu/drm/drm_client_event.c         | 18 ++++++++++
>  drivers/gpu/drm/drm_edid.c                 |  1 +
>  drivers/gpu/drm/i915/i915_switcheroo.c     | 11 +++++-
>  drivers/gpu/drm/nouveau/nouveau_vga.c      | 28 +++++++++------
>  drivers/gpu/drm/radeon/radeon_device.c     |  9 ++++-
>  drivers/gpu/vga/vga_switcheroo.c           | 41 +++++---------------
> --
>  drivers/video/fbdev/core/fbcon.c           |  8 -----
>  include/drm/drm_client.h                   | 14 ++++++++
>  include/drm/drm_client_event.h             |  3 ++
>  include/linux/vga_switcheroo.h             | 30 +++++++++-------
>  12 files changed, 122 insertions(+), 73 deletions(-)
> 
> 
> base-commit: cd8abe2554ec7eba16c1d48ab508732bf93534eb