radeonsi: clean up winsys creation

- unify the code
- choose radeon or amdgpu based on the DRM version, not based on which one
  succeeds first

src/gallium/auxiliary/target-helpers/drm_helper.h

@@ -161,23 +161,14 @@ pipe_r600_create_screen(int fd, const struct pipe_screen_config *config)
 #endif
 
 #ifdef GALLIUM_RADEONSI
-#include "radeon/radeon_winsys.h"
-#include "radeon/drm/radeon_drm_public.h"
-#include "amdgpu/drm/amdgpu_public.h"
 #include "radeonsi/si_public.h"
 
 struct pipe_screen *
 pipe_radeonsi_create_screen(int fd, const struct pipe_screen_config *config)
 {
-   struct radeon_winsys *rw;
+   struct pipe_screen *screen = radeonsi_screen_create(fd, config);
 
-   /* First, try amdgpu. */
-   rw = amdgpu_winsys_create(fd, config, radeonsi_screen_create);
-
-   if (!rw)
-      rw = radeon_drm_winsys_create(fd, config, radeonsi_screen_create);
-
-   return rw ? debug_screen_wrap(rw->screen) : NULL;
+   return screen ? debug_screen_wrap(screen) : NULL;
 }
 
 const char *radeonsi_driconf_xml =

src/gallium/drivers/radeonsi/si_pipe.c

@@ -42,6 +42,10 @@
 #include "vl/vl_decoder.h"
 #include "driver_ddebug/dd_util.h"
 
+#include "gallium/winsys/radeon/drm/radeon_drm_public.h"
+#include "gallium/winsys/amdgpu/drm/amdgpu_public.h"
+#include <xf86drm.h>
+
 static const struct debug_named_value debug_options[] = {
 	/* Shader logging options: */
 	{ "vs", DBG(VS), "Print vertex shaders" },
@@ -879,8 +883,9 @@ static bool si_is_parallel_shader_compilation_finished(struct pipe_screen *scree
 	return util_queue_fence_is_signalled(&sel->ready);
 }
 
-struct pipe_screen *radeonsi_screen_create(struct radeon_winsys *ws,
-					   const struct pipe_screen_config *config)
+static struct pipe_screen *
+radeonsi_screen_create_impl(struct radeon_winsys *ws,
+			    const struct pipe_screen_config *config)
 {
 	struct si_screen *sscreen = CALLOC_STRUCT(si_screen);
 	unsigned hw_threads, num_comp_hi_threads, num_comp_lo_threads, i;
@@ -1225,3 +1230,21 @@ struct pipe_screen *radeonsi_screen_create(struct radeon_winsys *ws,
 
 	return &sscreen->b;
 }
+
+struct pipe_screen *radeonsi_screen_create(int fd, const struct pipe_screen_config *config)
+{
+	drmVersionPtr version = drmGetVersion(fd);
+	struct radeon_winsys *rw = NULL;
+
+	switch (version->version_major) {
+	case 2:
+		rw = radeon_drm_winsys_create(fd, config, radeonsi_screen_create_impl);
+		break;
+	case 3:
+		rw = amdgpu_winsys_create(fd, config, radeonsi_screen_create_impl);
+		break;
+	}
+
+	drmFreeVersion(version);
+	return rw ? rw->screen : NULL;
+}

src/gallium/drivers/radeonsi/si_public.h

@@ -25,9 +25,6 @@
 #ifndef SI_PUBLIC_H
 #define SI_PUBLIC_H
 
-struct radeon_winsys;
-
-struct pipe_screen *radeonsi_screen_create(struct radeon_winsys *ws,
-					   const struct pipe_screen_config *config);
+struct pipe_screen *radeonsi_screen_create(int fd, const struct pipe_screen_config *config);
 
 #endif

src/gallium/targets/pipe-loader/pipe_radeonsi.c

@@ -1,23 +1,14 @@
 #include "state_tracker/drm_driver.h"
 #include "target-helpers/inline_debug_helper.h"
-#include "radeon/drm/radeon_drm_public.h"
-#include "radeon/radeon_winsys.h"
-#include "amdgpu/drm/amdgpu_public.h"
 #include "radeonsi/si_public.h"
 #include "util/xmlpool.h"
 
 static struct pipe_screen *
 create_screen(int fd, const struct pipe_screen_config *config)
 {
-   struct radeon_winsys *rw;
+   struct pipe_screen *screen = radeonsi_screen_create(fd, config);
 
-   /* First, try amdgpu. */
-   rw = amdgpu_winsys_create(fd, config, radeonsi_screen_create);
-
-   if (!rw)
-      rw = radeon_drm_winsys_create(fd, config, radeonsi_screen_create);
-
-   return rw ? debug_screen_wrap(rw->screen) : NULL;
+   return screen ? debug_screen_wrap(screen) : NULL;
 }
 
 static const char *driconf_xml =

src/gallium/winsys/amdgpu/drm/amdgpu_winsys.c

@@ -284,17 +284,9 @@ amdgpu_winsys_create(int fd, const struct pipe_screen_config *config,
 		     radeon_screen_create_t screen_create)
 {
    struct amdgpu_winsys *ws;
-   drmVersionPtr version = drmGetVersion(fd);
    amdgpu_device_handle dev;
    uint32_t drm_major, drm_minor, r;
 
-   /* The DRM driver version of amdgpu is 3.x.x. */
-   if (version->version_major != 3) {
-      drmFreeVersion(version);
-      return NULL;
-   }
-   drmFreeVersion(version);
-
    /* Look up the winsys from the dev table. */
    simple_mtx_lock(&dev_tab_mutex);
    if (!dev_tab)