[i845] unity-system-compositor fails to start: Failed to choose ARGB EGL config

Actually more important to Mir right now is how your system supports OpenGL|ES.

Can you please run:
    sudo apt-get install mesa-utils-extra
    es2_info

and paste the output from es2_info here?

From the installed/14.10 system:
es2_info: es2_info.c:158: make_x_window: Assertion `num_configs > 0' failed.
Aborted

"es2_info: es2_info.c:158: make_x_window: Assertion `num_configs > 0

Enough said. See enhancement bug 1420581 as a way forward.

Can you please attach the full output of glxinfo? There are more things I want to check...

From installed/14.10:

name of display: :0.0
display: :0 screen: 0
direct rendering: Yes
server glx vendor string: SGI
server glx version string: 1.4
server glx extensions:
    GLX_ARB_create_context, GLX_ARB_create_context_profile,
    GLX_ARB_fbconfig_float, GLX_ARB_framebuffer_sRGB, GLX_ARB_multisample,
    GLX_EXT_create_context_es2_profile, GLX_EXT_framebuffer_sRGB,
    GLX_EXT_import_context, GLX_EXT_texture_from_pixmap, GLX_EXT_visual_info,
    GLX_EXT_visual_rating, GLX_INTEL_swap_event, GLX_MESA_copy_sub_buffer,
    GLX_OML_swap_method, GLX_SGIS_multisample, GLX_SGIX_fbconfig,
    GLX_SGIX_pbuffer, GLX_SGIX_visual_select_group, GLX_SGI_swap_control
client glx vendor string: Mesa Project and SGI
client glx version string: 1.4
client glx extensions:
    GLX_ARB_create_context, GLX_ARB_create_context_profile,
    GLX_ARB_create_context_robustness, GLX_ARB_fbconfig_float,
    GLX_ARB_framebuffer_sRGB, GLX_ARB_get_proc_address, GLX_ARB_multisample,
    GLX_EXT_buffer_age, GLX_EXT_create_context_es2_profile,
    GLX_EXT_fbconfig_packed_float, GLX_EXT_framebuffer_sRGB,
    GLX_EXT_import_context, GLX_EXT_texture_from_pixmap, GLX_EXT_visual_info,
    GLX_EXT_visual_rating, GLX_INTEL_swap_event, GLX_MESA_copy_sub_buffer,
    GLX_MESA_multithread_makecurrent, GLX_MESA_query_renderer,
    GLX_MESA_swap_control, GLX_OML_swap_method, GLX_OML_sync_control,
    GLX_SGIS_multisample, GLX_SGIX_fbconfig, GLX_SGIX_pbuffer,
    GLX_SGIX_visual_select_group, GLX_SGI_make_current_read,
    GLX_SGI_swap_control, GLX_SGI_video_sync
GLX version: 1.4
GLX extensions:
    GLX_ARB_create_context, GLX_ARB_create_context_profile,
    GLX_ARB_fbconfig_float, GLX_ARB_framebuffer_sRGB,
    GLX_ARB_get_proc_address, GLX_ARB_multisample, GLX_EXT_framebuffer_sRGB,
    GLX_EXT_import_context, GLX_EXT_texture_from_pixmap, GLX_EXT_visual_info,
    GLX_EXT_visual_rating, GLX_INTEL_swap_event, GLX_MESA_copy_sub_buffer,
    GLX_MESA_multithread_makecurrent, GLX_MESA_query_renderer,
    GLX_MESA_swap_control, GLX_OML_swap_method, GLX_OML_sync_control,
    GLX_SGIS_multisample, GLX_SGIX_fbconfig, GLX_SGIX_pbuffer,
    GLX_SGIX_visual_select_group, GLX_SGI_make_current_read,
    GLX_SGI_swap_control, GLX_SGI_video_sync
OpenGL vendor string: Intel Open Source Technology Center
OpenGL renderer string: Mesa DRI Intel(R) 845G x86/MMX/SSE2
OpenGL version string: 1.3 Mesa 10.3.2
OpenGL extensions:
    GL_3DFX_texture_compression_FXT1, GL_AMD_shader_trinary_minmax,
    GL_ANGLE_texture_compression_dxt3, GL_ANGLE_texture_compression_dxt5,
    GL_APPLE_object_purgeable, GL_APPLE_packed_pixels,
    GL_APPLE_vertex_array_object, GL_ARB_clear_buffer_object,
    GL_ARB_compressed_texture_pixel_storage, GL_ARB_copy_buffer,
    GL_ARB_debug_output, GL_ARB_draw_buffers,
    GL_ARB_draw_elements_base_vertex, GL_ARB_explicit_attrib_location,
    GL_ARB_explicit_uniform_location, GL_ARB_framebuffer_object,
    GL_ARB_get_program_binary, GL_ARB_half_float_pixel,
    GL_ARB_internalformat_query, GL_ARB_invalidate_subdata,
    GL_ARB_map_buffer_alignment, GL_ARB_map_buffer_range, GL_ARB_multi_bind,
    GL_ARB_multisample, GL_ARB_multitexture, GL_ARB_pixel_buffer_...

Interesting, this is present: GL_ARB_shading_language_100

So there is still hope we can support your system with minimal changes to Mir (and Unity8 might work too). I think we just have to implement enhancement bug 1420581.

Syncing task from Mir.