Radeon HD5870: Can't get 60HZ monitor refresh rate

Submitted by Alexander

Assigned to Default DRI bug account

Description

Created attachment 132708
dmesg and xorg.log

When I set native monitor mode 1920x1200-60Hz, refresh rate is not switches to 60Hz. It is 42Hz only. Mode 1280x1024 works with 60Hz refresh rate.

xrandr --output DisplayPort-0 --mode 1920x1200 --rate 60 doesn't help.

GALLIUM_HUD="fps" glxgears shows 42HZ as well as monitor OSD menu.

Linux mint 18 live CD shows 42Hz too, but LMDE2 edition working with 60Hz

Help please to fix it!

dmesg and xorg.log is attached

OS: Debian 9.0, Driver: 7.7 (7.8)
Monitor: Dell 24" 1920x1200
Video card: ATI HD5870

Attachment 132708, "dmesg and xorg.log":
xorg+dmesg.log