https://bugs.freedesktop.org/show_bug.cgi?id=41121
Summary: Apple Thunderbolt display is not initialized when plugged into iMac 12,2 (Radeon 6870) Product: DRI Version: unspecified Platform: x86-64 (AMD64) OS/Version: Linux (All) Status: NEW Severity: normal Priority: medium Component: DRM/Radeon AssignedTo: dri-devel@lists.freedesktop.org ReportedBy: brad@fnarfbargle.com
Created an attachment (id=51518) --> (https://bugs.freedesktop.org/attachment.cgi?id=51518) Clean boot with nothing plugged in
This iMac has 2 "Thunderbolt" (mini-displayport connectors on the back). They will happily drive a pair of 1920x1200 DVI monitors with mini-displayport to DVI dongles, but will not look at the Apple "thunderbolt" monitor when plugged in.
It does work in OSX however.
If the monitor is plugged in at boot, the kernel appears to read the EDID correctly (the modes are displayed as what they should be), however it always fails to bring the displayport link up.
I've included 4 dmesg runs from clean boot to a single user console. 1) clean with no external monitors 2) clean with thunderbolt monitor at boot 3) clean with DVI at boot 4) (3) but with thunderbolt plugged in at about the 30s point. (This often reduces the machine to a steaming pile of molasses, almost like an interrupt storm but with no outward signs except a very slow console/processing.