winsys/radeon: add buffer_get_reloc_offset

Really fix the bug that was supposed to be fixed by commits 3e7cced4b and
a48bf02d: even when virtual addresses are used, the legacy relocation-based
method with offsets relative to the kernel's buffer object are used for
video submissions.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97969
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>

src/gallium/drivers/radeon/radeon_uvd.c

@@ -123,7 +123,7 @@ static void send_cmd(struct ruvd_decoder *dec, unsigned cmd,
 		set_reg(dec, RUVD_GPCOM_VCPU_DATA0, addr);
 		set_reg(dec, RUVD_GPCOM_VCPU_DATA1, addr >> 32);
 	} else {
-		off += dec->ws->buffer_get_virtual_address(buf);
+		off += dec->ws->buffer_get_reloc_offset(buf);
 		set_reg(dec, RUVD_GPCOM_VCPU_DATA0, off);
 		set_reg(dec, RUVD_GPCOM_VCPU_DATA1, reloc_idx * 4);
 	}

src/gallium/drivers/radeon/radeon_vce.c

@@ -549,7 +549,7 @@ void rvce_add_buffer(struct rvce_encoder *enc, struct pb_buffer *buf,
 		RVCE_CS(addr >> 32);
 		RVCE_CS(addr);
 	} else {
-		offset += enc->ws->buffer_get_virtual_address(buf);
+		offset += enc->ws->buffer_get_reloc_offset(buf);
 		RVCE_CS(reloc_idx * 4);
 		RVCE_CS(offset);
 	}

src/gallium/drivers/radeon/radeon_winsys.h

@@ -514,6 +514,18 @@ struct radeon_winsys {
      */
     uint64_t (*buffer_get_virtual_address)(struct pb_buffer *buf);
 
+    /**
+     * Return the offset of this buffer relative to the relocation base.
+     * This is only non-zero for sub-allocated buffers.
+     *
+     * This is only supported in the radeon winsys, since amdgpu uses virtual
+     * addresses in submissions even for the video engines.
+     *
+     * \param buf      A winsys buffer object
+     * \return         the offset for relocations
+     */
+    unsigned (*buffer_get_reloc_offset)(struct pb_buffer *buf);
+
     /**
      * Query the initial placement of the buffer from the kernel driver.
      */

src/gallium/winsys/radeon/drm/radeon_drm_bo.c

@@ -1339,6 +1339,16 @@ static uint64_t radeon_winsys_bo_va(struct pb_buffer *buf)
     return ((struct radeon_bo*)buf)->va;
 }
 
+static unsigned radeon_winsys_bo_get_reloc_offset(struct pb_buffer *buf)
+{
+    struct radeon_bo *bo = radeon_bo(buf);
+
+    if (bo->handle)
+        return 0;
+
+    return bo->va - bo->u.slab.real->va;
+}
+
 void radeon_drm_bo_init_functions(struct radeon_drm_winsys *ws)
 {
     ws->base.buffer_set_metadata = radeon_bo_set_metadata;
@@ -1352,5 +1362,6 @@ void radeon_drm_bo_init_functions(struct radeon_drm_winsys *ws)
     ws->base.buffer_is_user_ptr = radeon_winsys_bo_is_user_ptr;
     ws->base.buffer_get_handle = radeon_winsys_bo_get_handle;
     ws->base.buffer_get_virtual_address = radeon_winsys_bo_va;
+    ws->base.buffer_get_reloc_offset = radeon_winsys_bo_get_reloc_offset;
     ws->base.buffer_get_initial_domain = radeon_bo_get_initial_domain;
 }