scripts/runqemu: move render nodes check to runqemu from selftest

This will produce a more useful hint for those setting
up or testing virgl headless:

runqemu - ERROR - No render nodes found in /dev/dri: ['by-path', 'card0']. If /dev/dri/renderD* is absent due to lack of suitable GPU, 'modprobe vgem' will create one suitable for mesa llvmpipe software renderer.

as qemu itself isn't helpful:

alex@Zen2:/srv/storage/alex/yocto/build-64-alt$ qemu-system-x86_64 -display egl-headless
qemu-system-x86_64: egl: no drm render node available
qemu-system-x86_64: egl: render node init failed

(From OE-Core rev: cbbada6a6c9b0a2e97f7395117dad986555f2db9)

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/scripts/runqemu b/scripts/runqemu
index cedf4f62ad..58b0c191e1 100755
--- a/scripts/runqemu
+++ b/scripts/runqemu
@@ -1366,6 +1366,15 @@ class BaseConfig(object):
             raise RunQemuError("Failed to boot, QB_SYSTEM_NAME is NULL!")
         self.qemu_system = qemu_system
 
+    def check_render_nodes(self):
+        render_hint = """If /dev/dri/renderD* is absent due to lack of suitable GPU, 'modprobe vgem' will create one suitable for mesa llvmpipe software renderer."""
+        try:
+            content = os.listdir("/dev/dri")
+            if len([i for i in content if i.startswith('render')]) == 0:
+                raise RunQemuError("No render nodes found in /dev/dri: %s. %s" %(content, render_hint))
+        except FileNotFoundError:
+            raise RunQemuError("/dev/dri directory does not exist; no render nodes available on this machine. %s" %(render_hint))
+
     def setup_vga(self):
         if self.nographic == True:
             if self.sdl == True:
@@ -1403,6 +1412,7 @@ class BaseConfig(object):
 
             self.qemu_opt += ' -display '
             if self.egl_headless == True:
+                self.check_render_nodes()
                 self.set_dri_path()
                 self.qemu_opt += 'egl-headless,'
             else: