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

[Thomas Zimmermann]

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
---
 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