Issue: On host P520 with S03J3226A SBIOS platform, passthrough both
gfx and audio device to VM, the first time start VM after host bootup,
driver woule load fail.

Root cause: Passthrough both devices allows VFIO to do hot reset
on bridge, this reset clears register BIOS_SCRATCH_7 which is used
for judging if VBIOS has been post. Since in the first time driver
does not do BACO reset when loading, VBIOS would be post twice.

Solution: When running in passthrough mode, force enable BACO reset
in every time loading driver.

Notice: This is a workaround for SWDEV-187506 issue, passthrough two
devices to VM is required.

Signed-off-by: Jesse Zhang <zhexi.zh...@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/soc15.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/soc15.c 
b/drivers/gpu/drm/amd/amdgpu/soc15.c
index 9d33ba4..790099d 100644
--- a/drivers/gpu/drm/amd/amdgpu/soc15.c
+++ b/drivers/gpu/drm/amd/amdgpu/soc15.c
@@ -738,15 +738,16 @@ static bool soc15_need_reset_on_init(struct amdgpu_device 
*adev)
 {
        u32 sol_reg;
 
-       if (!amdgpu_passthrough(adev))
-               return false;
-
        if (adev->flags & AMD_IS_APU)
                return false;
 
        /* Check sOS sign of life register to confirm sys driver and sOS
         * are already been loaded.
         */
+
+       if (amdgpu_passthrough(adev))
+               return true;
+
        sol_reg = RREG32_SOC15(MP0, 0, mmMP0_SMN_C2PMSG_81);
        if (sol_reg)
                return true;
-- 
2.7.4

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