Topic: How do GPU's get their numbers? (Read 1733 times)

Naturally, see the Init Display First setting.
The order cards are initialized in is reflected in the BIOS device map (that measly 64k of memory which tends to get clogged up with the unnecessary mobo "goodies").

Some better-behaved bioses actually allow you to choose PEG1 or PEG2 (as in PCI Express Graphics) as the primary device.
I've yet to see a bios allowing me to select any PCIe slot for the primary GPU.

I did a quick search for a good reference to the PCI bus enumeration process and did not come up with anything right off the bat so this is from memory.  First in the xx:xx:xx number the first number is called the bus number.  They are assigned during the bus enumeration process.  This is done dynamically at boot up time.

Now PCI cards can use more than one bus number.  In fact your two boards are using a total of six bus numbers.  They are assigned depth first so your first board is using bus numbers 0D, 0E and 0F.  0D was used to get to the board and internal to the board there are two busses one for each device.

The second board is using 05, 06, and 07.  Again 05 will be the connection to the board and 06 and 07 are internal to the board.

All other PCI connected devices in your system are being assigned bus numbers and the assignments are based on the actual wiring of your devices.  The search is done and the busses are assigned depth first through all bridges, and devices.  Since is has been a long time since I have delt with this I may go back and look it up in some of the books I have and give you more detail - or maybe not.

If found on MSI 890FXA-GD70 MB that in moving cards around I got aticonfig all screwed up.  Nothing seemed to fix until I reset (not flashed) bios.  Then cards were back in the right order.  I think BIOS may have something to do with the order that OS sees the cards in.

AFAIK - with Afterburner (that is all I use) GPU1 will be the newest card (6850 over 5850 etc)

I am also interested to know this.

If I do aticonfig -lsa I get something like this for my two 6990's

* 0. 0f:00.0  AMD Radeon HD 6990
   1. 0e:00.0 AMD Radeon HD 6990
   2. 07:00.0 AMD Radeon HD 6990
   3. 06:00.0 AMD Radeon HD 6990

Now I have a theory that 0f means nearest to the motherboard, and other numbers decreasing away.
I also have a theory that the device numbers may depend on random factors, since I once say a device 2 (the last device)
in the middle of 3 cards. But its not a good theory. Here is another machine:

aticonfig -lsa

* 0. 0a:00.0 ATI Radeon HD 5800 Series
  1. 05:00.0 ATI Radeon HD 5800 Series
  2. 04:00.0 ATI Radeon HD 5800 Series

* - Default adapter
aticonfig --adapter=all --odgt

Adapter 0 - ATI Radeon HD 5800 Series
            Sensor 0: Temperature - 66.50 C

Adapter 1 - ATI Radeon HD 5800 Series
            Sensor 0: Temperature - 71.50 C

Adapter 2 - ATI Radeon HD 5800 Series
            Sensor 0: Temperature - 96.00 C


Now I know the middle card has a broken fan. So really doesnt figure!! That has to be the hot one, surely?

Anyone offer suggestions?

Another thing I tried is switching the fans high or low. This can be done using an aticonfig command and setting the DISPLAY variable.

So, more questions than answers I am afraid?

Or could it be that it depends on motherboard wiring and there is a correlation between the small number in aticonfig --lsa and the position, just not necessiarily linear?

Sorry, sounds like a main board problem to me. The numbering is usually decided by which PCIE port they are placed in.

Are you using 2 GPUs? Sometimes the numbering starts with 0, and sometimes with 1. If using 1 and 2 isn't working, try running 0 and 1 and see if both cards are loaded. Good luck!

Lately I have a problem whenever I want to do something to GPU # 2, the system always crashes. I have tried to swap the cards around, and even into another machine, and they all work fine, but GPU # 2 seems to always be locking up.
was working fine before the weekend...what changed? I moved my rack into the garage...I am hoping i did not dameage the motherboard in any way...

the question is...what gives the cards the gpu numbers, and if when the cards swap slots on the motherboard, do the gpu numbers change?