[all variants] plymouth during boot problem

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http://ubuntuforums.org – during bootup, on my system with the radeon kms driver, my displays turn off (both showing 'no signal' messages) between grub and lightdm. grub displays normally, lightdm graphical login displays normally and x displays and works normally. the plymouth progress screen displays normally during shutdown. can anyone give me some advice on how to troubleshoot why plymouth won't display a progress screen during bootup? i'd at least like to be able to force a text mode plymouth to display during boot, if the graphical one can't be gotten working, so that i will actually _see_ something if/when th (Hardware)