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I am getting the following error when I boot my Dell Precision 390. Everything appears to be working fine, but I would like to understand what the error means and how to fix it. I believe it started happening when I plugged in my second video card, but that card is working great.

Error allocating Mem BAR for PCI device 04/00/0
Error allocating Mem BAR for PCI device 05/00/0
Error allocating Mem BAR for PCI device 05/02/0
Error allocating Mem BAR for PCI device 05/05/0
Error allocating Mem BAR for PCI device 05/04/0
Error allocating Mem BAR for PCI device 05/04/0
Error allocating Mem BAR for PCI device 05/05/0
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2 Answers 2

up vote 3 down vote accepted

For PCI and PCIe devices, a BAR is a Base Address Register that is used by the BIOS or OS to tell the device what physical addresses to map its memory resources into. Most PCI devices in your system requests a certain amount of memory space, and the BIOS tries to fit them all below 4 GB in order to ensure compatibility with 32-bit operating systems. It sounds like your computer has 4 GB of RAM and that both video cards contain large amounts of RAM.

In those error messages, the location of the device is specified as bus/device/function. I have access to a Dell Precision 390 and it appears that all of the onboard devices on that system are on PCI bus number 0, so your errors probably refer to a device that you have plugged into a PCI or PCIe slot. Each PCIe slot gets its own bus number, so bus number 5 might actually correspond to a multi-function PCIe device such as a sound card or video capture card.

You should be able to track down which devices are 4/0/0, 5/2/0, 5/4/0, and 5/5/0 once the OS is loaded, if the BIOS doesn't print this information before booting. (Note that this assumes that the OS doesn't reassign the PCI bus numbers on boot, which would destroy the evidence; if that happens, the OS may be patching up the mess that the BIOS left.)

If you use Windows, you can find the PCI bus/device/function numbers of a device by right clicking on it in Device Manager, selecting Properties..., and looking at Location: on the General tab. (On Vista and Windows 7, this same information also shows up when you select the Details tab and choose Location information from the Property listbox.)

If you use Linux, you can find the PCI bus/device/function numbers using the lspci command.

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Which version of Windows has that? WinXP does not seem to have the Location Information there. –  Kevin Panko Sep 11 '09 at 16:09
    
Even if you do not use Linux, a bootable CD with Linux will work fine for this. –  Kevin Panko Sep 11 '09 at 16:10
    
@Kevin Panko: Thanks for pointing that out. "Details >> Property >> Location information" was in Vista. But it turns out that both XP and Vista display that information on the "General" tab, so I'll update my answer. –  bk1e Sep 11 '09 at 16:39

The documentation lists that code: Error allocating Mem BAR for PCI Device

The system encountered a problem while trying to configure an expansion card or integrated on-board devices.

If the device number points to an expansion card, the card can be removed. See "Troubleshooting Expansion Cards" in "Troubleshooting Your System."

If the device number points to a an on-board device, disable the device. See "Using the System Setup Program" in your User's Guide for details.

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I want to fix the problem, not get rid of a card that appears to be working fine. How do I know if the device number is a card or an onboard device? –  user836 Jul 15 '09 at 13:48

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