[PATCH] drm/amd/amdgpu: Add modeset module parameter support

[Zhen Ni <nizhen@uniontech.com>]

Nomodeset kernel parameter is for all graphics cards. Amdgpu cannot
be set separately in some scenarios, such as hybrid graphics(i + a).
Add modeset module parameter for amdgpu to set kernel mode separately.

Signed-off-by: Zhen Ni <nizhen@uniontech.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 429fcdf28836..856a70370e3c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -107,6 +107,7 @@
 #define KMS_DRIVER_MINOR	48
 #define KMS_DRIVER_PATCHLEVEL	0
 
+int amdgpu_modeset = -1;
 int amdgpu_vram_limit;
 int amdgpu_vis_vram_limit;
 int amdgpu_gart_size = -1; /* auto */
@@ -199,6 +200,13 @@ struct amdgpu_watchdog_timer amdgpu_watchdog_timer = {
 	.period = 0x0, /* default to 0x0 (timeout disable) */
 };
 
+/**
+ * DOC: modeset (int)
+ * Disable/Enable kernel modesetting (1 = enable, 0 = disable, -1 = auto (default)).
+ */
+MODULE_PARM_DESC(modeset, "Disable/Enable kernel modesetting");
+module_param_named(modeset, amdgpu_modeset, int, 0400);
+
 /**
  * DOC: vramlimit (int)
  * Restrict the total amount of VRAM in MiB for testing.  The default is 0 (Use full VRAM).
@@ -2753,7 +2761,10 @@ static int __init amdgpu_init(void)
 {
 	int r;
 
-	if (drm_firmware_drivers_only())
+	if (drm_firmware_drivers_only() && amdgpu_modeset == -1)
+		amdgpu_modeset = 0;
+
+	if (amdgpu_modeset == 0)
 		return -EINVAL;
 
 	r = amdgpu_sync_init();
-- 
2.20.1