Can't get VGA video on Carrizo R7 gpu, only HDMI

[MONSSA]

Hello. This is my first time trying to report a bug, I hope I'm in the 
right place.

I have a PC with MSI A68HM-E33 V2 motherboard, and AMD A8-7680 CPU with 
Radeon R7.

I'm running Debian 9 Stretch, Kernel~4.19.0-0.bpo.6-amd64, using amdgpu 
driver, and I get video only on the HDMI output.

xrandr only lists the HDMI output as connected, and a DVI output 
disconnected. The motherboard doesn't have DVI connector, only VGA and HDMI.

I tried forcing video output on the DVI interface, but I didn't get any 
video on VGA port, even though the desktop was arranged to spread across 
both screens.

I tried several options for the kernel module, such as "exp_hw_support" 
and "cik_support" didn't fully knowing what they did, to no avail.

Of course I have two monitors plugged in to both connectors, and I ruled 
out hardware problems (such as burned connector) because I changed the 
HDD and installed windows, with the official AMD windows drivers I get 
video working fine on both monitors, so monitors, cables and ports are 
working.

The motherboard has the latest BIOS available.

Thanks in advance for any help.

Here is some info, tell me if you need any more:

00:01.0 VGA compatible controller: Advanced Micro Devices, Inc. 
[AMD/ATI] Carrizo (rev e2) (prog-if 00 [VGA controller])
     Subsystem: Micro-Star International Co., Ltd. [MSI] Wani [Radeon 
R5/R6/R7 Graphics]
     Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- 
Stepping- SERR- FastB2B- DisINTx+
     Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- 
<TAbort- <MAbort- >SERR- <PERR- INTx-
     Latency: 0, Cache Line Size: 64 bytes
     Interrupt: pin A routed to IRQ 36
     Region 0: Memory at c0000000 (64-bit, prefetchable) [size=256M]
     Region 2: Memory at d0000000 (64-bit, prefetchable) [size=8M]
     Region 4: I/O ports at f000 [size=256]
     Region 5: Memory at feb00000 (32-bit, non-prefetchable) [size=256K]
     Expansion ROM at 000c0000 [disabled] [size=128K]
     Capabilities: [48] Vendor Specific Information: Len=08 <?>
     Capabilities: [50] Power Management version 3
         Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA 
PME(D0-,D1+,D2+,D3hot+,D3cold-)
         Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
     Capabilities: [58] Express (v2) Root Complex Integrated Endpoint, 
MSI 00
         DevCap:    MaxPayload 256 bytes, PhantFunc 0
             ExtTag+ RBE+
         DevCtl:    Report errors: Correctable- Non-Fatal- Fatal- 
Unsupported-
             RlxdOrd+ ExtTag+ PhantFunc- AuxPwr- NoSnoop+
             MaxPayload 128 bytes, MaxReadReq 512 bytes
         DevSta:    CorrErr- UncorrErr- FatalErr- UnsuppReq- AuxPwr- 
TransPend-
         DevCap2: Completion Timeout: Not Supported, TimeoutDis-, LTR-, 
OBFF Not Supported
         DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR-, 
OBFF Disabled
     Capabilities: [a0] MSI: Enable+ Count=1/1 Maskable- 64bit+
         Address: 00000000fee00000  Data: 0000
     Capabilities: [100 v1] Vendor Specific Information: ID=0001 Rev=1 
Len=010 <?>
     Capabilities: [270 v1] #19
     Capabilities: [2b0 v1] Address Translation Service (ATS)
         ATSCap:    Invalidate Queue Depth: 00
         ATSCtl:    Enable+, Smallest Translation Unit: 00
     Capabilities: [2c0 v1] Page Request Interface (PRI)
         PRICtl: Enable+ Reset-
         PRISta: RF- UPRGI- Stopped+
         Page Request Capacity: 00000020, Page Request Allocation: 00000020
     Capabilities: [2d0 v1] Process Address Space ID (PASID)
         PASIDCap: Exec- Priv-, Max PASID Width: 10
         PASIDCtl: Enable+ Exec- Priv-
     Kernel driver in use: amdgpu
     Kernel modules: amdgpu


-- 
Julián Metelski
Departamento IT
Monitoring Station S.A.
Calle 48 n° 812
La Plata (B1900AHN) - BA - ARG
Tel/Fax: (+54) 221 425 3355