Do AMD GPUs need a dummy plug to work without a monitor?

[salfter]

Received a Radeon 7750 today to hold me over until the Jalapeños arrive...put it in an idle box with an on-board nVidia GPU (GeForce 7-series equivalent, so no CUDA or OpenCL on it).  It already had Gentoo on it, so it just needed drivers and bfgminer.

AFAICT, X is working (haven't plugged it in, but the messages are consistent with it running). Starting bfgminer with the -n option ends with "error -1: getting device IDs", after some messages about the OpenCL vendor, platform, and version (all of which mention AMD and not nVidia).

The computer is in a closet with a power cord and network cable plugged in. I haven't yet plugged in a monitor. I know some nVidia GPUs won't fire up properly if no monitor is plugged in or the monitor is off. Is this also an issue with AMD GPUs? Could this also be a result of not disabling the on board video in BIOS setup?

[crazyates]

First of all, I <3 Gentoo.

I never had to use dummy plugs when I used linux. Dummy plugs were only used on Windows machines with older drivers (think 11.6 or something). In recent months, I had to use dummy plugs to let CGMiner control the card through ADL, but again, I dont think that's a linux issue.

What driver did you install, and did it install with the -opencl USE flag?

[AndrewBUD]

I don't use dummy plugs on my rigs.... i forget what driver version i run but "newer"

[salfter]

What driver did you install, and did it install with the -opencl USE flag?

x11-drivers/ati-drivers-12.6, which doesn't appear to have any USE flags pertaining to OpenCL.  It pulled in the following:

• sys-power/acpid-2.0.16-r1
• virtual/modutils-0
• app-admin/eselect-opencl-1.1.0-r1
• virtual/pkgconfig-0
• x11-proto/xf86miscproto-0.9.3

bfgminer (2.7.5, modified ebuild from the bitcoin overlay) pulled in these:

• dev-libs/jansson-2.3.1
• x11-libs/amd-adl-sdk-4.0
• virtual/opencl-0-r2

In /etc/make.conf, VIDEO_CARDS was changed from nvidia to fglrx.  These USE flags are active: adl, cpumining, ncurses, opencl, sse2, sse2_4way, sse4, and udev.

X produces this output when it starts up:

Code:

X.Org X Server 1.11.2
Release Date: 2011-11-04
X Protocol Version 11, Revision 0
Build Operating System: Linux 3.1.10-gentoo-r1 x86_64 Gentoo
Current Operating System: Linux lanbox 3.2.5-gentoo #1 SMP Tue Feb 14 09:11:58 PST 2012 x86_64
Kernel command line: root=/dev/sda1 vga=791 
Build Date: 26 January 2012  09:55:15PM
 
Current version of pixman: 0.24.0
        Before reporting problems, check http://wiki.x.org
        to make sure that you have the latest version.
Markers: (--) probed, (**) from config file, (==) default setting,
        (++) from command line, (!!) notice, (II) informational,
        (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.0.log", Time: Sat Sep  1 09:43:11 2012
(==) Using config file: "/etc/X11/xorg.conf"
(==) Using config directory: "/etc/X11/xorg.conf.d"
(==) Using system config directory "/usr/share/X11/xorg.conf.d"
(EE) Failed to load module "dri" (module does not exist, 0)
(EE) Failed to load module "dri2" (module does not exist, 0)
(WW) fglrx: No matching Device section for instance (BusID PCI:0@2:0:1) found

Here's something I did since last night: I needed to put a longer power cord on the box, so I shut it down, swapped cords, and rebooted.  I started X in a screen session, then started bfgminer in benchmark mode.  Without any tweaking, it's getting about 115-116 MH/s.  I didn't change any settings.  I don't know what the reboot would've done, but it's working now.  It's still not plugged into a monitor.

[salfter]

...and with minimal tweaking (mostly copying some settings from my nVidia miners), it's now getting about 120 MH/s.  That makes it about 20x faster than my 9500GTs.

 

Next step will be to migrate bitcoind and p2pool onto this box.

This, BTW, is what I'm running...factory-overclocked to 880 MHz.

Update: In the past 7 minutes, I have nineten rejected shares and no accepted shares.  That sounds troubling. Maybe I should walk away for a bit and see what it does longer-term.

[salfter]

...and another update: the high reject rate was with long polling turned off.

Derp.

Four minutes so far...4 accepted, 2 rejected.

Also, with intensity at 11, I'm getting ~134 MH/s.

[Zenitur]

You need edit /etc/X11/xorg.conf. This is my configuration file (integrated ATi Radeon HD 3200 and ATi Radeon HD 5850):

Code:

Section "ServerLayout"
	Identifier     "aticonfig Layout"
	Screen      0  "aticonfig-Screen[0]-0" 0 0
	Screen         "amdcccle-Screen[2]-0" 800 0
EndSection

Section "Module"
EndSection

Section "Monitor"
	Identifier   "0-CRT1"
	Option	    "VendorName" "ATI Proprietary Driver"
	Option	    "ModelName" "Generic Autodetecting Monitor"
	Option	    "DPMS" "true"
	Option	    "PreferredMode" "800x600"
	Option	    "TargetRefresh" "60"
	Option	    "Position" "0 0"
	Option	    "Rotate" "normal"
	Option	    "Disable" "false"
EndSection

Section "Monitor"
	Identifier   "1-??????? ?? ?????????"
	Option	    "VendorName" "ATI Proprietary Driver"
	Option	    "ModelName" "Generic Autodetecting Monitor"
	Option	    "DPMS" "true"
	Option	    "PreferredMode" "640x480"
	Option	    "TargetRefresh" "60"
	Option	    "Position" "0 0"
	Option	    "Rotate" "normal"
	Option	    "Disable" "false"
EndSection

Section "Device"
	Identifier  "aticonfig-Device[0]-0"
	Driver      "fglrx"
	Option	    "Monitor-CRT1" "0-CRT1"
	BusID       "PCI:1:5:0"
EndSection

Section "Device"
	Identifier  "amdcccle-Device[2]-0"
	Driver      "fglrx"
	Option	    "Monitor-??????? ?? ?????????" "1-??????? ?? ?????????"
	BusID       "PCI:2:0:0"
EndSection

Section "Screen"
	Identifier "aticonfig-Screen[0]-0"
	Device     "aticonfig-Device[0]-0"
	DefaultDepth     24
	SubSection "Display"
		Viewport   0 0
		Depth     24
	EndSubSection
EndSection

Section "Screen"
	Identifier "amdcccle-Screen[2]-0"
	Device     "amdcccle-Device[2]-0"
	DefaultDepth     24
	SubSection "Display"
		Viewport   0 0
		Depth     24
	EndSubSection
EndSection

It was created by graphical tool amdcccle, because of aticonfig --initial did wrong config file. I may use only one monitor, but must define two.