From 0fa57cbfa7039e4a579f1a4a0956982b654335c8 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Wed, 31 Jul 2024 16:41:34 +0100 Subject: [PATCH] hw/display/virtio-gpu: Improve "opengl is not available" error message MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If the user tries to use the virtio-gpu-gl device but the display backend doesn't have OpenGL support enabled, we currently print a rather uninformative error message: $ qemu-system-aarch64 -M virt -device virtio-gpu-gl qemu-system-aarch64: -device virtio-gpu-gl: opengl is not available Since OpenGL is not enabled on display frontends by default, users are quite likely to run into this. Improve the error message to be more specific and to suggest to the user a path forward. Note that the case of "user tried to enable OpenGL but the display backend doesn't handle it" is caught elsewhere first, so we can assume that isn't the problem: $ qemu-system-aarch64 -M virt -device virtio-gpu-gl -display curses,gl=on qemu-system-aarch64: OpenGL is not supported by the display (Use of error_append_hint() requires us to add an ERRP_GUARD() to the function, as noted in include/qapi/error.h.) With this commit we now produce the hopefully more helpful error: $ ./build/x86/qemu-system-aarch64 -M virt -device virtio-gpu-gl qemu-system-aarch64: -device virtio-gpu-gl: The display backend does not have OpenGL support enabled It can be enabled with '-display BACKEND,gl=on' where BACKEND is the name of the display backend to use. Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2443 Signed-off-by: Peter Maydell Acked-by: Marc-André Lureau Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Alex Bennée Message-ID: <20240731154136.3494621-2-peter.maydell@linaro.org> Signed-off-by: Philippe Mathieu-Daudé --- hw/display/virtio-gpu-gl.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/hw/display/virtio-gpu-gl.c b/hw/display/virtio-gpu-gl.c index 952820a425..29d20b0132 100644 --- a/hw/display/virtio-gpu-gl.c +++ b/hw/display/virtio-gpu-gl.c @@ -106,6 +106,7 @@ static void virtio_gpu_gl_reset(VirtIODevice *vdev) static void virtio_gpu_gl_device_realize(DeviceState *qdev, Error **errp) { + ERRP_GUARD(); VirtIOGPU *g = VIRTIO_GPU(qdev); #if HOST_BIG_ENDIAN @@ -119,7 +120,12 @@ static void virtio_gpu_gl_device_realize(DeviceState *qdev, Error **errp) } if (!display_opengl) { - error_setg(errp, "opengl is not available"); + error_setg(errp, + "The display backend does not have OpenGL support enabled"); + error_append_hint(errp, + "It can be enabled with '-display BACKEND,gl=on' " + "where BACKEND is the name of the display backend " + "to use.\n"); return; }