diff options
Diffstat (limited to 'results/classifier/accel-gemma3:12b/vmm/1888964')
| -rw-r--r-- | results/classifier/accel-gemma3:12b/vmm/1888964 | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/results/classifier/accel-gemma3:12b/vmm/1888964 b/results/classifier/accel-gemma3:12b/vmm/1888964 new file mode 100644 index 000000000..9ce17f20d --- /dev/null +++ b/results/classifier/accel-gemma3:12b/vmm/1888964 @@ -0,0 +1,41 @@ + +Segfault using GTK display with dmabuf (iGVT-g) on Wayland + +When using... + a) Intel virtualized graphics (iGVT-g) with dmabuf output + b) QEMU's GTK display with GL output enabled (-display gtk,gl=on) + c) A Wayland compositor (Sway in my case) +a segfault occurs at some point on boot (I guess as soon as the guest starts using the virtual graphics card?) + +The origin is the function dpy_gl_scanout_dmabuf in ui/console.c, where it calls + con->gl->ops->dpy_gl_scanout_dmabuf(con->gl, dmabuf); +However, the ops field (struct DisplayChangeListenerOps) does not have dpy_gl_scanout_dmabuf set because it is set to dcl_gl_area_ops which does not have dpy_gl_scanout_dmabuf set. +Only dcl_egl_ops has dpy_gl_scanout_dmabuf set. +Currently, the GTK display uses EGL on X11 displays, but GtkGLArea on Wayland. This can be observed in early_gtk_display_init() in ui/gtk.c, where it says (simplified code): + +if (opts->has_gl && opts->gl != DISPLAYGL_MODE_OFF) { + if (GDK_IS_WAYLAND_DISPLAY(gdk_display_get_default())) { + gtk_use_gl_area = true; + gtk_gl_area_init(); + } else { + DisplayGLMode mode = opts->has_gl ? opts->gl : DISPLAYGL_MODE_ON; + gtk_egl_init(mode); + } +} + +To reproduce the findings above, add this assertion to dpy_gl_scanout_dmabuf: + assert(con->gl->ops->dpy_gl_scanout_dmabuf); +This will make the segfault turn into an assertion failure. + +A workaround is to force QEMU to use GDK's X11 backend (using GDK_BACKEND=x11). + +Note: This might be a duplicate of 1775011, however the information provided in that bug report is not sufficient to make the assertion. + +QEMU version: b0ce3f021e0157e9a5ab836cb162c48caac132e1 (from Git master branch) +OS: Arch Linux, Kernel Version 5.17.0-1 + +Relevant flags of the QEMU invocation: +qemu-system-x86_64 \ + -vga none \ + -device vfio-pci-nohotplug,sysfsdev="$GVT_DEV",romfile="${ROMFILE}",display=on,x-igd-opregion=on,ramfb=on \ + -display gtk,gl=on \ No newline at end of file |