drm/radeon: Add RADEON_INFO_VA_UNMAP_WORKING query

commit 3bc980bf upstream.

This tells userspace that it's safe to use the RADEON_VA_UNMAP operation
of the DRM_RADEON_GEM_VA ioctl.

(NOTE: Backporting this commit requires at least backports of commits
26d4d129,
48afbd70 and
c29c0876 as well, otherwise using
RADEON_VA_UNMAP runs into trouble)
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/gpu/drm/radeon/radeon_kms.c

@@ -547,6 +547,9 @@ static int radeon_info_ioctl(struct drm_device *dev, void *data, struct drm_file
 		else
 			*value = 1;
 		break;
+	case RADEON_INFO_VA_UNMAP_WORKING:
+		*value = true;
+		break;
 	default:
 		DRM_DEBUG_KMS("Invalid request %d\n", info->request);
 		return -EINVAL;

include/uapi/drm/radeon_drm.h

@@ -1034,6 +1034,7 @@ struct drm_radeon_cs {
 #define RADEON_INFO_VRAM_USAGE		0x1e
 #define RADEON_INFO_GTT_USAGE		0x1f
 #define RADEON_INFO_ACTIVE_CU_COUNT	0x20
+#define RADEON_INFO_VA_UNMAP_WORKING	0x25
 
 struct drm_radeon_info {
 	uint32_t		request;