drm/amd/amdgpu: sdma resume fail during S4 on CI

BugLink: http://bugs.launchpad.net/bugs/1621113

commit 10ea9434 upstream.

SDMA could be fail in the thaw() and restore() processes, do software reset
if each SDMA engine is busy.
Signed-off-by: JimQu <Jim.Qu@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/gpu/drm/amd/amdgpu/cik_sdma.c

@@ -52,6 +52,7 @@ static void cik_sdma_set_ring_funcs(struct amdgpu_device *adev);
 static void cik_sdma_set_irq_funcs(struct amdgpu_device *adev);
 static void cik_sdma_set_buffer_funcs(struct amdgpu_device *adev);
 static void cik_sdma_set_vm_pte_funcs(struct amdgpu_device *adev);
+static int cik_sdma_soft_reset(void *handle);
 
 MODULE_FIRMWARE("radeon/bonaire_sdma.bin");
 MODULE_FIRMWARE("radeon/bonaire_sdma1.bin");
@@ -1030,6 +1031,8 @@ static int cik_sdma_resume(void *handle)
 {
 	struct amdgpu_device *adev = (struct amdgpu_device *)handle;
 
+	cik_sdma_soft_reset(handle);
+
 	return cik_sdma_hw_init(adev);
 }