https://bugs.freedesktop.org/show_bug.cgi?id=42162
--- Comment #24 from Vova vova7890@mail.ru --- if via ssh try to start X, in dmesg see that:
[ 236.672326] [drm:radeon_dp_link_train_cr] *ERROR* displayport link status failed [ 236.672327] [drm:radeon_dp_link_train_cr] *ERROR* clock recovery failed
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