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

Set the framebuffer info for drivers that support VGA switcheroo. Only
affects the amdgpu and nouveau drivers, which use VGA switcheroo and
generic fbdev emulation. For other drivers, this does nothing.

This fixes a potential regression in the console code. Both, amdgpu and
nouveau, invoked vga_switcheroo_client_fb_set() from their internal fbdev
code. But the call got lost when the drivers switched to the generic
emulation.

Fixes: 087451f3 ("drm/amdgpu: use generic fb helpers instead of setting up AMD own's.")
Fixes: 4a16dd9d ("drm/nouveau/kms: switch to drm fbdev helpers")
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Evan Quan <evan.quan@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Hawking Zhang <Hawking.Zhang@amd.com>
Cc: Likun Gao <Likun.Gao@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: Stanley Yang <Stanley.Yang@amd.com>
Cc: "Tianci.Yin" <tianci.yin@amd.com>
Cc: Xiaojian Du <Xiaojian.Du@amd.com>
Cc: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Cc: YiPeng Chai <YiPeng.Chai@amd.com>
Cc: Somalapuram Amaranath <Amaranath.Somalapuram@amd.com>
Cc: Bokun Zhang <Bokun.Zhang@amd.com>
Cc: Guchun Chen <guchun.chen@amd.com>
Cc: Hamza Mahfooz <hamza.mahfooz@amd.com>
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Solomon Chiu <solomon.chiu@amd.com>
Cc: Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Marek Olšák" <marek.olsak@amd.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
Cc: dri-devel@lists.freedesktop.org
Cc: nouveau@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v5.17+
Link: https://patchwork.freedesktop.org/patch/msgid/20230116115425.13484-3-tzimmermann@suse.de

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>
@@ -1909,6 +1911,11 @@ 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;
 }