[PATCH] drm/fb-helper: Set framebuffer for vga-switcheroo clients

[Daniel Vetter]

On Wed, Jan 11, 2023 at 04:38:13PM +0100, Thomas Zimmermann wrote:
> Set the framebuffer info for drivers that support VGA switcheroo. Only
> affects the amdgpu driver, which uses VGA switcheroo and generic fbdev
> emulation. For other drivers, this does nothing.
> 
> Amdgpu's lastclose helper called vga_switcheroo_process_delayed_switch().
> But as amdgpu uses generic fbdev emulation, it's better to call the helper
> from drm_lastclose(), after the kernel client's screen has been restored.
> So all drivers and clients can benefit. Radeon and nouveau with modernized
> fbdev code are possible candidates.
> 
> There was an earlier patchset to do something similar. [1]
> 
> Suggested-by: Alexander Deucher <Alexander.Deucher at amd.com>
> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
> Link: https://lore.kernel.org/amd-gfx/20221020143603.563929-1-alexander.deucher@amd.com/ # 1

Indeed, vga_switcheroo_client_fb_set is a no-op if no client is registered
on that pdev.

Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>

t-b/ack from amd would be still good I think (or maybe they'll pick this
one up so it goes through their CI).
-Daniel

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu.h     |  1 -
>  drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c |  1 -
>  drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c | 12 ------------
>  drivers/gpu/drm/drm_fb_helper.c         |  8 ++++++++
>  drivers/gpu/drm/drm_file.c              |  3 +++
>  5 files changed, 11 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> index 63c921c55fb9..7120b9b6e580 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> @@ -1330,7 +1330,6 @@ extern const int amdgpu_max_kms_ioctl;
>  
>  int amdgpu_driver_load_kms(struct amdgpu_device *adev, unsigned long flags);
>  void amdgpu_driver_unload_kms(struct drm_device *dev);
> -void amdgpu_driver_lastclose_kms(struct drm_device *dev);
>  int amdgpu_driver_open_kms(struct drm_device *dev, struct drm_file *file_priv);
>  void amdgpu_driver_postclose_kms(struct drm_device *dev,
>  				 struct drm_file *file_priv);
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> index ebc6e6cbe2ab..02d636f781a2 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> @@ -2784,7 +2784,6 @@ static const struct drm_driver amdgpu_kms_driver = {
>  	    DRIVER_SYNCOBJ_TIMELINE,
>  	.open = amdgpu_driver_open_kms,
>  	.postclose = amdgpu_driver_postclose_kms,
> -	.lastclose = amdgpu_driver_lastclose_kms,
>  	.ioctls = amdgpu_ioctls_kms,
>  	.num_ioctls = ARRAY_SIZE(amdgpu_ioctls_kms),
>  	.dumb_create = amdgpu_mode_dumb_create,
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
> index 7aa7e52ca784..886739576d3d 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
> @@ -1104,18 +1104,6 @@ int amdgpu_info_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
>  /*
>   * Outdated mess for old drm with Xorg being in charge (void function now).
>   */
> -/**
> - * amdgpu_driver_lastclose_kms - drm callback for last close
> - *
> - * @dev: drm dev pointer
> - *
> - * Switch vga_switcheroo state after last close (all asics).
> - */
> -void amdgpu_driver_lastclose_kms(struct drm_device *dev)
> -{
> -	drm_fb_helper_lastclose(dev);
> -	vga_switcheroo_process_delayed_switch();
> -}
>  
>  /**
>   * amdgpu_driver_open_kms - drm callback for open
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 427631706128..5e445c61252d 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -30,7 +30,9 @@
>  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>  
>  #include <linux/console.h>
> +#include <linux/pci.h>
>  #include <linux/sysrq.h>
> +#include <linux/vga_switcheroo.h>
>  
>  #include <drm/drm_atomic.h>
>  #include <drm/drm_drv.h>
> @@ -1940,6 +1942,7 @@ static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,
>  					 int preferred_bpp)
>  {
>  	struct drm_client_dev *client = &fb_helper->client;
> +	struct drm_device *dev = fb_helper->dev;
>  	struct drm_fb_helper_surface_size sizes;
>  	int ret;
>  
> @@ -1961,6 +1964,11 @@ static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,
>  		return ret;
>  
>  	strcpy(fb_helper->fb->comm, "[fbcon]");
> +
> +	/* Set the fb info for vgaswitcheroo clients. Does nothing otherwise. */
> +	if (dev_is_pci(dev->dev))
> +		vga_switcheroo_client_fb_set(to_pci_dev(dev->dev), fb_helper->info);
> +
>  	return 0;
>  }
>  
> diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
> index a51ff8cee049..314c309db9a3 100644
> --- a/drivers/gpu/drm/drm_file.c
> +++ b/drivers/gpu/drm/drm_file.c
> @@ -38,6 +38,7 @@
>  #include <linux/pci.h>
>  #include <linux/poll.h>
>  #include <linux/slab.h>
> +#include <linux/vga_switcheroo.h>
>  
>  #include <drm/drm_client.h>
>  #include <drm/drm_drv.h>
> @@ -460,6 +461,8 @@ void drm_lastclose(struct drm_device * dev)
>  		drm_legacy_dev_reinit(dev);
>  
>  	drm_client_dev_restore(dev);
> +
> +	vga_switcheroo_process_delayed_switch();
>  }
>  
>  /**
> -- 
> 2.39.0
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch