This one may have been going on for some time - I haven't updated the old Intel Mac Mini in a while.
And by "not updated" I also mean that it's some really old user-space: the machine is running F14, and cannot be updated to anything newer without having to reinstall everything because of a stupid small /boot partition. So it's not going to happen. But maybe somebody cares about the i915 warning anyway?
Linus
--- WARNING: CPU: 1 PID: 2846 at drivers/gpu/drm/i915/intel_sdvo.c:1378 intel_sdvo_get_config+0x158/0x160() SDVO pixel multiplier mismatch, port: 0, encoder: 1 Modules linked in: snd_hda_codec_idt snd_hda_intel snd_hda_codec snd_hwdep CPU: 1 PID: 2846 Comm: Xorg Not tainted 3.11.0-rc3-00208-gbe1e8d7-dirty #19 Hardware name: Apple Computer, Inc. Macmini1,1/Mac-F4208EC8, BIOS MM11.88Z.0055.B03.0604071521 04/07/06 00000000 00000000 ef0afa54 c1597bbb c1737ea4 ef0afa84 c10392ca c1737e6c ef0afab0 00000b1e c1737ea4 00000562 c12dfbe8 c12dfbe8 ef0afb14 00000000 f697ec00 ef0afa9c c103936e 00000009 ef0afa94 c1737e6c ef0afab0 ef0afadc Call Trace: [<c1597bbb>] dump_stack+0x41/0x56 [<c10392ca>] warn_slowpath_common+0x7a/0xa0 [<c103936e>] warn_slowpath_fmt+0x2e/0x30 [<c12dfbe8>] intel_sdvo_get_config+0x158/0x160 [<c12c3220>] check_crtc_state+0x1e0/0xb10 [<c12cdc7d>] intel_modeset_check_state+0x29d/0x7c0 [<c12dfe5c>] intel_sdvo_dpms+0x5c/0xa0 [<c12985de>] drm_mode_obj_set_property_ioctl+0x40e/0x420 [<c1298625>] drm_mode_connector_property_set_ioctl+0x35/0x40 [<c1289294>] drm_ioctl+0x3e4/0x540 [<c10fc1a2>] do_vfs_ioctl+0x72/0x570 [<c10fc72f>] SyS_ioctl+0x8f/0xa0 [<c159b7fa>] sysenter_do_call+0x12/0x22 ---[ end trace 7ce940aff1366d60 ]---