Lubuntu 14.04 on Powermac G5

New LTS ubuntu (14.04) for PowerPC has been released.  I installed on my powermac G5 (2.0G Dualcore, late2005, GeForce6600LE).  Ubuntu 10.04LTS works fine but the previous version 12.04LTS doesn't work due to videocard problem.  Now, Lubuntu 14.04 PPC is easily installed from the live cd.  Problems about sound and network indicator occurred but could be fixed according to PowerPCKnownIssues.
....However, the video problem appears again after the newer kernel 3.13.0-27.50 was updated.

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lubuntu 15.04
lubuntu 14.04.2
ubuntu MATE