Nouveau - Aug 2024 - [PATCH v2 1/9] drm: Do delayed switcheroo in drm_lastclose()

Amdgpu and nouveau call vga_switcheroo_process_delayed_switch() from
their lastclose callbacks. Call it from drm_lastclose(), so that the
driver functions can finally be removed. Only PCI devices with enabled
switcheroo do the delayed switching. The call has no effect on other
hardware.

v2:
- move change to drm_lastclose() (Sima)
- update docs for vga_switcheroo_process_delayed_switch()

Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
---
 drivers/gpu/drm/drm_file.c       | 4 ++++
 drivers/gpu/vga/vga_switcheroo.c | 3 +--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
index 714e42b05108..513bef816ae9 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>
@@ -404,6 +405,9 @@ void drm_lastclose(struct drm_device * dev)
 	drm_dbg_core(dev, "driver lastclose completed\n");
 
 	drm_client_dev_restore(dev);
+
+	if (dev_is_pci(dev->dev))
+		vga_switcheroo_process_delayed_switch();
 }
 
 /**
diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
index 365e6ddbe90f..18f2c92beff8 100644
--- a/drivers/gpu/vga/vga_switcheroo.c
+++ b/drivers/gpu/vga/vga_switcheroo.c
@@ -926,8 +926,7 @@ static void vga_switcheroo_debugfs_init(struct vgasr_priv
*priv)
 /**
  * vga_switcheroo_process_delayed_switch() - helper for delayed switching
  *
- * Process a delayed switch if one is pending. DRM drivers should call this
- * from their ->lastclose callback.
+ * Process a delayed switch if one is pending.
  *
  * Return: 0 on success. -EINVAL if no delayed switch is pending, if the client
  * has unregistered in the meantime or if there are other clients blocking the
-- 
2.46.0

On Mon, Aug 12, 2024 at 10:28:22AM +0200, Thomas Zimmermann
wrote:
> Amdgpu and nouveau call vga_switcheroo_process_delayed_switch() from
> their lastclose callbacks. Call it from drm_lastclose(), so that the
> driver functions can finally be removed. Only PCI devices with enabled
> switcheroo do the delayed switching. The call has no effect on other
> hardware.
> 
> v2:
> - move change to drm_lastclose() (Sima)
> - update docs for vga_switcheroo_process_delayed_switch()
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
A bit an aside: The entire vgaswitcheroo code is still a midlayer mess,
where the locking is at the wrong layers resulting in the can_switch check
potentially being racy. But that's a different can of worms.

Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> ---
>  drivers/gpu/drm/drm_file.c       | 4 ++++
>  drivers/gpu/vga/vga_switcheroo.c | 3 +--
>  2 files changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
> index 714e42b05108..513bef816ae9 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>
> @@ -404,6 +405,9 @@ void drm_lastclose(struct drm_device * dev)
>  	drm_dbg_core(dev, "driver lastclose completed\n");
>  
>  	drm_client_dev_restore(dev);
> +
> +	if (dev_is_pci(dev->dev))
> +		vga_switcheroo_process_delayed_switch();
>  }
>  
>  /**
> diff --git a/drivers/gpu/vga/vga_switcheroo.c
b/drivers/gpu/vga/vga_switcheroo.c
> index 365e6ddbe90f..18f2c92beff8 100644
> --- a/drivers/gpu/vga/vga_switcheroo.c
> +++ b/drivers/gpu/vga/vga_switcheroo.c
> @@ -926,8 +926,7 @@ static void vga_switcheroo_debugfs_init(struct
vgasr_priv *priv)
>  /**
>   * vga_switcheroo_process_delayed_switch() - helper for delayed switching
>   *
> - * Process a delayed switch if one is pending. DRM drivers should call
this
> - * from their ->lastclose callback.
> + * Process a delayed switch if one is pending.
>   *
>   * Return: 0 on success. -EINVAL if no delayed switch is pending, if the
client
>   * has unregistered in the meantime or if there are other clients blocking
the
> -- 
> 2.46.0
> 
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

On Mon, Aug 12, 2024 at 4:30?AM Thomas Zimmermann <tzimmermann at suse.de>
wrote:
>
> Amdgpu and nouveau call vga_switcheroo_process_delayed_switch() from
> their lastclose callbacks. Call it from drm_lastclose(), so that the
> driver functions can finally be removed. Only PCI devices with enabled
> switcheroo do the delayed switching. The call has no effect on other
> hardware.
>
> v2:
> - move change to drm_lastclose() (Sima)
> - update docs for vga_switcheroo_process_delayed_switch()
>
> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
Reviewed-by: Alex Deucher <alexander.deucher at amd.com>
> ---
>  drivers/gpu/drm/drm_file.c       | 4 ++++
>  drivers/gpu/vga/vga_switcheroo.c | 3 +--
>  2 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
> index 714e42b05108..513bef816ae9 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>
> @@ -404,6 +405,9 @@ void drm_lastclose(struct drm_device * dev)
>         drm_dbg_core(dev, "driver lastclose completed\n");
>
>         drm_client_dev_restore(dev);
> +
> +       if (dev_is_pci(dev->dev))
> +               vga_switcheroo_process_delayed_switch();
>  }
>
>  /**
> diff --git a/drivers/gpu/vga/vga_switcheroo.c
b/drivers/gpu/vga/vga_switcheroo.c
> index 365e6ddbe90f..18f2c92beff8 100644
> --- a/drivers/gpu/vga/vga_switcheroo.c
> +++ b/drivers/gpu/vga/vga_switcheroo.c
> @@ -926,8 +926,7 @@ static void vga_switcheroo_debugfs_init(struct
vgasr_priv *priv)
>  /**
>   * vga_switcheroo_process_delayed_switch() - helper for delayed switching
>   *
> - * Process a delayed switch if one is pending. DRM drivers should call
this
> - * from their ->lastclose callback.
> + * Process a delayed switch if one is pending.
>   *
>   * Return: 0 on success. -EINVAL if no delayed switch is pending, if the
client
>   * has unregistered in the meantime or if there are other clients blocking
the
> --
> 2.46.0
>

I do not know which list this is.  How can I get these emails to stop?

Thank you.

On Mon, Aug 12, 2024 at 3:40?AM Thomas Zimmermann <tzimmermann at suse.de>
wrote:
> Amdgpu and nouveau call vga_switcheroo_process_delayed_switch() from
> their lastclose callbacks. Call it from drm_lastclose(), so that the
> driver functions can finally be removed. Only PCI devices with enabled
> switcheroo do the delayed switching. The call has no effect on other
> hardware.
>
> v2:
> - move change to drm_lastclose() (Sima)
> - update docs for vga_switcheroo_process_delayed_switch()
>
> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
> ---
>  drivers/gpu/drm/drm_file.c       | 4 ++++
>  drivers/gpu/vga/vga_switcheroo.c | 3 +--
>  2 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
> index 714e42b05108..513bef816ae9 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>
> @@ -404,6 +405,9 @@ void drm_lastclose(struct drm_device * dev)
>         drm_dbg_core(dev, "driver lastclose completed\n");
>
>         drm_client_dev_restore(dev);
> +
> +       if (dev_is_pci(dev->dev))
> +               vga_switcheroo_process_delayed_switch();
>  }
>
>  /**
> diff --git a/drivers/gpu/vga/vga_switcheroo.c
> b/drivers/gpu/vga/vga_switcheroo.c
> index 365e6ddbe90f..18f2c92beff8 100644
> --- a/drivers/gpu/vga/vga_switcheroo.c
> +++ b/drivers/gpu/vga/vga_switcheroo.c
> @@ -926,8 +926,7 @@ static void vga_switcheroo_debugfs_init(struct
> vgasr_priv *priv)
>  /**
>   * vga_switcheroo_process_delayed_switch() - helper for delayed switching
>   *
> - * Process a delayed switch if one is pending. DRM drivers should call
> this
> - * from their ->lastclose callback.
> + * Process a delayed switch if one is pending.
>   *
>   * Return: 0 on success. -EINVAL if no delayed switch is pending, if the
> client
>   * has unregistered in the meantime or if there are other clients
> blocking the
> --
> 2.46.0
>
>
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