The new vkms virtual display code is atomic so there is
no need to call drm_helper_disable_unused_functions()
when it is enabled. Doing so can result in a segfault.
When the driver switched from the old virtual display code
to the new atomic virtual display code, it was missed that
we enable virtual display unconditionally under SR-IOV
so the checks here missed that case. Add the missing
check for SR-IOV.
There is no equivalent of this patch for Linus' tree
because the relevant code no longer exists. This patch
is only relevant to kernels 5.15 and 5.16.
Fixes: 84ec374bd580 ("drm/amdgpu: create amdgpu_vkms (v4)")
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # 5.15.x
Cc: hgoffin@xxxxxxxxxx
---
drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c
index cd0acbea75da..d58ab9deb028 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c
@@ -341,7 +341,8 @@ int amdgpu_fbdev_init(struct amdgpu_device *adev)
}
/* disable all the possible outputs/crtcs before entering KMS mode */
- if (!amdgpu_device_has_dc_support(adev) && !amdgpu_virtual_display)
+ if (!amdgpu_device_has_dc_support(adev) && !amdgpu_virtual_display &&
+ !amdgpu_sriov_vf(adev))
drm_helper_disable_unused_functions(adev_to_drm(adev));
drm_fb_helper_initial_config(&rfbdev->helper, bpp_sel);
--
2.35.3
