Two video cards, two monitors - Problem of second monitor in slackware 14.2

I have a problem to configure a second monitor on my slackware 14.2.
I currently have two monitors, one on an onboard intel video card and one on an amd off board.
The amd driver seems to load, the main monitor works, however, the second monitor does not display an image. But it is not in standby mode.
the start light is in blue (color) mode.

Code:bash-4.3# inxi -Gxx
Graphics: Device-1: Intel Xeon E3-1200 v2/3rd Gen Core processor Graphics vendor: Gigabyte driver: i915 v: kernel
bus ID: 00:02.0 chip ID: 8086:0152
Device-2: Advanced Micro Devices [AMD/ATI] Turks PRO [Radeon HD 6570/7570/8550] vendor: XFX Pine driver: radeon
v: kernel bus ID: 01:00.0 chip ID: 1002:6759
Display: server: X.Org 1.18.3 driver: ati,intel,radeon unloaded: modesetting,vesa alternate: fbdev
compositor: kwin_x11 resolution: 1280x1024~60Hz
OpenGL: renderer: Gallium 0.4 on AMD TURKS (DRM 2.43.0 LLVM 3.8.0) v: 3.3 Mesa 11.2.2 compat-v: 3.0
direct render: YesCode:bash-4.3# inxi
CPU: Quad Core Intel Core i5-3330 (-MCP-) speed/min/max: 1902/1600/3200 MHz Kernel: 4.4.14 x86_64 Up: 1h 11m
Mem: 1485.8/7681.1 MiB (19.3%) Storage: 3.18 TiB (16.7% used) Procs: 203 Shell: bash 4.3.46 inxi: 3.0.37Code:bash-4.3# xrandr --listproviders
Providers: number : 2
Provider 0: id: 0xaa cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 6 outputs: 3 associated providers: 0 name:TURKS @ pci:0000:01:00.0
Provider 1: id: 0x45 cap: 0xb, Source Output, Sink Output, Sink Offload crtcs: 4 outputs: 2 associated providers: 0 name:IntelCode:bash-4.3# xrandr -q
Screen 0: minimum 320 x 200, current 1280 x 1024, maximum 16384 x 16384
HDMI-0 disconnected (normal left inverted right x axis y axis)
DVI-0 disconnected (normal left inverted right x axis y axis)
VGA-1 connected primary 1280x1024+0+0 (normal left inverted right x axis y axis) 338mm x 270mm
1280x1024 60.02*+ 75.02
1152x864 75.00
1024x768 75.08 60.00
800x600 75.00 60.32
640x480 75.00 60.00
720x400 70.08Code:bash-4.3# lspci
00:00.0 Host bridge: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor DRAM Controller (rev 09)
00:01.0 PCI bridge: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor PCI Express Root Port (rev 09)
00:02.0 VGA compatible controller: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor Graphics Controller (rev 09)
00:16.0 Communication controller: Intel Corporation 6 Series/C200 Series Chipset Family MEI Controller #1 (rev 04)
00:1a.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #2 (rev 05)
00:1b.0 Audio device: Intel Corporation 6 Series/C200 Series Chipset Family High Definition Audio Controller (rev 05)
00:1c.0 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 1 (rev b5)
00:1c.4 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 5 (rev b5)
00:1d.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #1 (rev 05)
00:1f.0 ISA bridge: Intel Corporation H61 Express Chipset Family LPC Controller (rev 05)
00:1f.2 IDE interface: Intel Corporation 6 Series/C200 Series Chipset Family 4 port SATA IDE Controller (rev 05)
00:1f.3 SMBus: Intel Corporation 6 Series/C200 Series Chipset Family SMBus Controller (rev 05)
00:1f.5 IDE interface: Intel Corporation 6 Series/C200 Series Chipset Family 2 port SATA IDE Controller (rev 05)
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Turks PRO [Radeon HD 6570/7570/8550]
01:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Turks/Whistler HDMI Audio [Radeon HD 6000 Series]
03:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 06)bash-4.3# cat /var/log/Xorg.0.log --> Link : https://pastebin.com/B0N9U8fb