Thanks Herminio i had been test after read this post first time
but on 7800gtx i continue have problems. ... the same issue reported couple monts ago in the qemu kvm ppc
the X start but a message from gdm appear with "system encounter a problem ... bla bla bla ... reboot"
on radeonhd the X continue crashing.
im thinking probably is the pagesize of the kernel reported by an user some days a go can be the key.
Subject: Fwd: startx goes to black screen with mouse pointer
Date: Tue, 30 Jun 2015 16:14:45 -0500
Take a look at this thread. This may help you.
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