2009-apple-gmux-allow-switching-to-igpu-at-probe.patch

From bd8e785c74e22978648ced004552eb9c137f1eb6 Mon Sep 17 00:00:00 2001
From: Orlando Chamberlain <orlandoch.dev@gmail.com>
Date: Fri, 10 Feb 2023 22:45:00 +1100
Subject: [PATCH 9/9] apple-gmux: allow switching to igpu at probe

This means user don't need to set the gpu-power-prefs efivar to use the
igpu while runtime switching isn't working, so macOS will be unaffected.

This isn't really upstreamable, what we want upstream is the ability to
switch at runtime (so both gpus need to be able to probe the eDP panel).

Based off of work by Kerem Karabay <kekrby@gmail.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c |  3 +++
 drivers/gpu/vga/vga_switcheroo.c        |  7 +------
 drivers/pci/vgaarb.c                    |  1 +
 drivers/platform/x86/apple-gmux.c       | 18 ++++++++++++++++++
 4 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 81edf66dbea8..8f3daf28665b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -2051,6 +2051,9 @@ static int amdgpu_pci_probe(struct pci_dev *pdev,
 	int ret, retry = 0, i;
 	bool supports_atomic = false;
 
+	if (vga_switcheroo_client_probe_defer(pdev))
+		return -EPROBE_DEFER;
+
 	/* skip devices which are owned by radeon */
 	for (i = 0; i < ARRAY_SIZE(amdgpu_unsupported_pciidlist); i++) {
 		if (amdgpu_unsupported_pciidlist[i] == pdev->device)
diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
index 365e6ddbe90f..cf357cd3389d 100644
--- a/drivers/gpu/vga/vga_switcheroo.c
+++ b/drivers/gpu/vga/vga_switcheroo.c
@@ -438,12 +438,7 @@ find_active_client(struct list_head *head)
 bool vga_switcheroo_client_probe_defer(struct pci_dev *pdev)
 {
 	if ((pdev->class >> 16) == PCI_BASE_CLASS_DISPLAY) {
-		/*
-		 * apple-gmux is needed on pre-retina MacBook Pro
-		 * to probe the panel if pdev is the inactive GPU.
-		 */
-		if (apple_gmux_present() && pdev != vga_default_device() &&
-		    !vgasr_priv.handler_flags)
+		if (apple_gmux_present() && !vgasr_priv.handler_flags)
 			return true;
 	}
 
diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index 5e6b1eb54c64..1f11701d37d1 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -143,6 +143,7 @@ void vga_set_default_device(struct pci_dev *pdev)
 	pci_dev_put(vga_default);
 	vga_default = pci_dev_get(pdev);
 }
+EXPORT_SYMBOL_GPL(vga_set_default_device);
 
 /**
  * vga_remove_vgacon - deactivate VGA console
diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
index 1417e230edbd..e69785af8e1d 100644
--- a/drivers/platform/x86/apple-gmux.c
+++ b/drivers/platform/x86/apple-gmux.c
@@ -21,6 +21,7 @@
 #include <linux/delay.h>
 #include <linux/pci.h>
 #include <linux/vga_switcheroo.h>
+#include <linux/vgaarb.h>
 #include <linux/debugfs.h>
 #include <acpi/video.h>
 #include <asm/io.h>
@@ -107,6 +108,10 @@ struct apple_gmux_config {
 
 # define MMIO_GMUX_MAX_BRIGHTNESS	0xffff
 
+static bool force_igd;
+module_param(force_igd, bool, 0);
+MODULE_PARM_DESC(force_idg, "Switch gpu to igd on module load. Make sure that you have apple-set-os set up and the iGPU is in `lspci -s 00:02.0`. (default: false) (bool)");
+
 static u8 gmux_pio_read8(struct apple_gmux_data *gmux_data, int port)
 {
 	return inb(gmux_data->iostart + port);
@@ -945,6 +950,19 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
 	gmux_enable_interrupts(gmux_data);
 	gmux_read_switch_state(gmux_data);
 
+	if (force_igd) {
+		struct pci_dev *pdev;
+
+		pdev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(2, 0));
+		if (pdev) {
+			pr_info("Switching to IGD");
+			gmux_switchto(VGA_SWITCHEROO_IGD);
+			vga_set_default_device(pdev);
+		} else {
+			pr_err("force_idg is true, but couldn't find iGPU at 00:02.0! Is apple-set-os working?");
+		}
+	}
+
 	/*
 	 * Retina MacBook Pros cannot switch the panel's AUX separately
 	 * and need eDP pre-calibration. They are distinguishable from
-- 
2.43.0