# Radeon external display on DVI port not recognized

## Punchcutter

I'm installing a dual head setup on a Dell tower, with an internal Intel graphics chip and a Radeon HD 7570 on PCI bus.

```
# lspci | grep -i vga

00:02.0 VGA compatible controller: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor Graphics Controller (rev 09)

01:00.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI Turks PRO [Radeon HD 7570]

```

Intel-driven display is working fine, but the system is not recognizing the monitor on the Radeon card. That monitor is an older VGA-type, attached to a DVI port on the card with a DVI-VGA adaptor. Everything works fine under Win7 (dual boot). In Gentoo, if I do xrandr, I see:

```
# xrandr

Screen 0: minimum 320 x 200, current 1280 x 1024, maximum 32767 x 32767

VGA1 connected 1280x1024+0+0 (normal left inverted right x axis y axis) 376mm x 301mm

   1280x1024      60.0*+   75.0

   1152x864       75.0

   1024x768       75.1     60.0

   800x600        75.0     60.3

   640x480        75.0     60.0

   720x400        70.1

HDMI1 disconnected (normal left inverted right x axis y axis)

DP1 disconnected (normal left inverted right x axis y axis)

```

The HDMI port is on the Intel motherboard adapter, but the DisplayPort (DP1, right?) is on the Radeon card. So if DP1 is seen, why is my DVI -> VGA not being seen?  It looks like I have kernel stuff set up properly, and radeon module loaded:

```
# zgrep -i radeon /proc/config.gz

CONFIG_DRM_RADEON=m

# CONFIG_DRM_RADEON_KMS is not set

CONFIG_FB_RADEON=m

CONFIG_FB_RADEON_I2C=y

CONFIG_FB_RADEON_BACKLIGHT=y

# CONFIG_FB_RADEON_DEBUG is not set

```

```
# lsmod | grep -i rade

radeon                858404  0

ttm                    58739  1 radeon

drm_kms_helper         26569  2 i915,radeon

cfbfillrect             3714  2 i915,radeon

cfbimgblt               2039  2 i915,radeon

cfbcopyarea             3350  2 i915,radeon

fb                     51085  7 i915,fbcon,drm_kms_helper,radeon,softcursor,tileblit,bitblit

backlight               4248  2 video,radeon

```

I also merged radeontool and radeon-ucode, but neither of these seems helpful. The radeontool doesn't really tell me anything useful, beyond that it sees the card.

I'm running a recent kernel (3.8.13) and latest stable (amd64) xorg-server and drivers. Any advice or help with this will be gratefully received.

----------

## chithanh

radeontool or radeon-ucode don't help you there. You need >=xrandr-1.4 and set the radeon's VGA output as sink (If intel is primary). See "man xrandr" for more details.

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## Punchcutter

Thanks! I've upgraded my xrandr to 1.4 and looked at the man page, but.... it's really not very helpful. That's being generous. I have to classify this as "still very poorly documented functionality"  :Sad: 

I googled around and found this fairly helpful discussion. However even this is insufficient for me to really figure out what I need to do.

On a practical note, I tried doing xrandr --listproviders, but it doesn't show my Radeon card at all:

```
# xrandr --listproviders

Providers: number : 1

Provider 0: id: 0x45 cap: 0xb, Source Output, Sink Output, Sink Offload crtcs: 3 outputs: 3 associated providers: 0 name:Intel

```

I take this as a rather bad sign  :Sad: 

After spending some time on this, I remembered an old email exchange I had a few years ago with someone in which they seemed to suggest that unifying two different GPUs into a single X desktop was something that was impossible at the time in Xorg, even though I had thought it must be something obviously possible. Even as I was attempting to do the same thing on my current install, I had forgotten about that email. Now I think I understand what this is all about.... these new features in 1.4 are the incipient attempt to fix that situation..... no?

Any further pointers are much appreciated! I suppose I can find an easy solution if I just get a monitor with an HDMI input, and connect it to my Intel adaptor, thus circumventing the problem of two GPUs.

----------

## chithanh

It is possible to use multiple GPUs since xrandr 1.4.

You need to ensure that you have the kernel and X drivers and firmware for the radeon card correctly set up, see http://www.gentoo.org/doc/en/xorg-config.xml

----------

## Punchcutter

Thanks again, chithanh.... so, now I believe I have my radeon drivers, firmware, etc all set up properly.... even rebuilt my xorg-server, just for kicks  :Smile:  rebooted, of course...

Just calling plain old xrandr still does not show me any more possible outputs, just the same as I've seen before:

```
# xrandr

Screen 0: minimum 320 x 200, current 1280 x 1024, maximum 32767 x 32767

VGA1 connected 1280x1024+0+0 (normal left inverted right x axis y axis) 376mm x 301mm

   1280x1024      60.0*+   75.0

   1152x864       75.0

   1024x768       75.1     60.0

   800x600        75.0     60.3

   640x480        75.0     60.0

   720x400        70.1

HDMI1 disconnected (normal left inverted right x axis y axis)

DP1 disconnected (normal left inverted right x axis y axis)

```

HOWEVER, I do now get this:

```
# xrandr --listproviders

Providers: number : 2

Provider 0: id: 0x87 cap: 0xb, Source Output, Sink Output, Sink Offload crtcs: 3 outputs: 3 associated providers: 1 name:Intel

Provider 1: id: 0x57 cap: 0xd, Source Output, Source Offload, Sink Offload crtcs: 6 outputs: 2 associated providers: 1 name:radeon

```

Now if I run the xrandr commands, both commands, both ways (not being sure which is right), I find that each command will simply output an error if I try to call it with the providers the reverse of what it thinks is possible. But then, if I do:

```
xrandr --setprovideroffloadsink 1 0
```

I just get my bash prompt back with no obvious result. OTOH, if I do:

```
xrandr --setprovideroutputsource 0 1
```

my screen (the usual one that works  :Smile: ) goes black, and I have to force a reboot.

Any more hints?  :Very Happy: 

----------

## Ant P.

Your video outputs aren't physically connected to the radeon so trying to use --setprovideroutputsource in that way will never work.

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## Punchcutter

Ant P., my second monitor is physically connected to the Radeon (3rd party) card, although through a DVI>VGA adaptor.

I didn't mention earlier than when I boot up, a small chunk of the usual startup messages (just about 20 lines) is mirrored onto the second monitor. So something is going on there... it's not completely hopeless  :Smile:  Just not sure where to go from here.

----------

