[PATCH v1 3/4] drm/amdgpu: Implement the is_boot_device callback function

[Sui Jingfeng]

From: Sui Jingfeng <suijingfeng at loongson.cn>

[why]

The vga_is_firmware_default() defined in drivers/pci/vgaarb.c is
arch-dependent, it's a dummy on non-x86 architectures currently.
This made VGAARB lost an important condition for the arbitration.
It could still be wrong even if we remove the #ifdef and #endif guards.
because the PCI bar will move (resource re-allocation).

[how]

The device that owns the firmware framebuffer should be the default boot
device. This patch adds an arch-independent function to enforce this rule.
The vgaarb subsystem will call back to amdgpu_is_boot_device() function
when drm/amdgpu is successfully bound to an AMDGPU device.

Cc: Alex Deucher <alexander.deucher at amd.com>
Cc: Christian Konig <christian.koenig at amd.com>
Cc: Pan Xinhui <Xinhui.Pan at amd.com>
Cc: David Airlie <airlied at gmail.com>
Cc: Daniel Vetter <daniel at ffwll.ch>
Cc: Hawking Zhang <Hawking.Zhang at amd.com>
Cc: Mario Limonciello <mario.limonciello at amd.com>
Cc: Lijo Lazar <lijo.lazar at amd.com>
Cc: YiPeng Chai <YiPeng.Chai at amd.com>
Cc: Bokun Zhang <Bokun.Zhang at amd.com>
CC: Likun Gao <Likun.Gao at amd.com>
Signed-off-by: Sui Jingfeng <suijingfeng at loongson.cn>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index c5bdf6eff29e..2f54250f9d58 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -3673,6 +3673,15 @@ static const struct attribute *amdgpu_dev_attributes[] = {
 	NULL
 };
 
+static bool amdgpu_is_boot_device(struct pci_dev *pdev)
+{
+	struct drm_device *dev = pci_get_drvdata(pdev);
+	struct amdgpu_device *adev = drm_to_adev(dev);
+	struct amdgpu_gmc *gmc = &adev->gmc;
+
+	return drm_aperture_contain_firmware_fb(gmc->aper_base, gmc->aper_size);
+}
+
 /**
  * amdgpu_device_init - initialize the driver
  *
@@ -4082,7 +4091,8 @@ int amdgpu_device_init(struct amdgpu_device *adev,
 	/* this will fail for cards that aren't VGA class devices, just
 	 * ignore it */
 	if ((adev->pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA)
-		vga_client_register(adev->pdev, amdgpu_device_vga_set_decode, NULL);
+		vga_client_register(adev->pdev, amdgpu_device_vga_set_decode,
+				    amdgpu_is_boot_device);
 
 	px = amdgpu_device_supports_px(ddev);
 
-- 
2.25.1