2 nvidia cards, only one fb

madtowner · 07-20-06, 06:54 PM

I have 2 nvidia cards (GeForce 6600GT PCI express) and would like to write directly to /dev/fb1 to the second monitor. Only one listing is in /proc/fb so the second framebuffer does not work. If I enter "cat /proc/fb" then I get
0 VESA VGA

but the second framebuffer does not show up(expected "32 VESA VGA")

Any ideas on how to set up the second framebuffer?

**Thunderbird** · 07-21-06, 01:52 AM

At system startup only one videocard is actually initialized. Some magic (int10) stuff. This is part of the problem. The second issue is that actually linux doesn't support the stuff you want to do yet. The whole console system is actually targetted at a single user at the moment.

People are trying to fix the problems and improve framebuffer support. The linuxconsole project is woring on this (http://linuxconsole.sourceforge.net/) but I don't know what the status of it is and how usefull it is already.

madtowner · 07-21-06, 08:34 AM

Thanks for the information. Any suggestions on alternative ways to implement my needs? I need to draw bitmaps to the second display. I have no requirements for windows or user input(no mouse, keyboard) with the second display.

**Thunderbird** · 07-21-06, 10:50 AM

You could run a second Xserver for the card. Normally when you run two Xservers but won't be 'on' at the same time because in general only one keyboard/mouse is connected. Because of this when you switch to the second Xserver the first one turns black. These days I believe there's a 'null' or 'void' input driver which you can select. This allows you to run a second Xserver without any input devices which is what you want. By setting the correct DISPLAY variable you can draw things to it.

pe1chl · 07-21-06, 11:29 AM

When you just want to have two X screens there is no need to run two servers. A single server can run two separate displays as :0.0 and :0.1 and you can run programs on the second display with DISPLAY=:0.1 without problem with input devices.

**Thunderbird** · 07-21-06, 12:11 PM

In case of separate X screens you can still reach the second screen by moving the mouse over. In the void way both are 100% separate and they can even be run as a different user.

SaTaN0rX · 07-21-06, 03:42 PM

and there is some evdev input driver, so you can have some real multi-user setup

07-20-06, 06:54 PM	#1
madtowner Registered User Join Date: Jul 2006 Posts: 4	2 nvidia cards, only one fb I have 2 nvidia cards (GeForce 6600GT PCI express) and would like to write directly to /dev/fb1 to the second monitor. Only one listing is in /proc/fb so the second framebuffer does not work. If I enter "cat /proc/fb" then I get 0 VESA VGA but the second framebuffer does not show up(expected "32 VESA VGA") Any ideas on how to set up the second framebuffer?

07-21-06, 01:52 AM	#2
Thunderbird Join Date: Jul 2002 Location: Netherlands, Europe Posts: 2,105	Re: 2 nvidia cards, only one fb At system startup only one videocard is actually initialized. Some magic (int10) stuff. This is part of the problem. The second issue is that actually linux doesn't support the stuff you want to do yet. The whole console system is actually targetted at a single user at the moment. People are trying to fix the problems and improve framebuffer support. The linuxconsole project is woring on this (http://linuxconsole.sourceforge.net/) but I don't know what the status of it is and how usefull it is already.

07-21-06, 08:34 AM	#3
madtowner Registered User Join Date: Jul 2006 Posts: 4	Re: 2 nvidia cards, only one fb Thanks for the information. Any suggestions on alternative ways to implement my needs? I need to draw bitmaps to the second display. I have no requirements for windows or user input(no mouse, keyboard) with the second display.

07-21-06, 10:50 AM	#4
Thunderbird Join Date: Jul 2002 Location: Netherlands, Europe Posts: 2,105	Re: 2 nvidia cards, only one fb You could run a second Xserver for the card. Normally when you run two Xservers but won't be 'on' at the same time because in general only one keyboard/mouse is connected. Because of this when you switch to the second Xserver the first one turns black. These days I believe there's a 'null' or 'void' input driver which you can select. This allows you to run a second Xserver without any input devices which is what you want. By setting the correct DISPLAY variable you can draw things to it.

07-21-06, 11:29 AM	#5
pe1chl Registered User Join Date: Aug 2003 Posts: 1,026	Re: 2 nvidia cards, only one fb When you just want to have two X screens there is no need to run two servers. A single server can run two separate displays as :0.0 and :0.1 and you can run programs on the second display with DISPLAY=:0.1 without problem with input devices.

07-21-06, 12:11 PM	#6
Thunderbird Join Date: Jul 2002 Location: Netherlands, Europe Posts: 2,105	Re: 2 nvidia cards, only one fb In case of separate X screens you can still reach the second screen by moving the mouse over. In the void way both are 100% separate and they can even be run as a different user.

07-21-06, 03:42 PM	#7
SaTaN0rX Registered User Join Date: Apr 2005 Posts: 86	Re: 2 nvidia cards, only one fb and there is some evdev input driver, so you can have some real multi-user setup

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