Messages in this thread | | | Date | Thu, 24 Feb 2005 14:22:19 -0600 | From | Terence Ripperda <> | Subject | 64-bit pci bar on a 32-bit kernel |
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Hello,
we've gotten a customer report of a problem whereby our framebuffer is not visible through the kernel. the kernel data structures in struct pci_dev have bar1 (our framebuffer) set to 0, and the bar does not appear in /proc/pci.
after a little investigation, it appears that the bios allocated a 64-bit bar in pci config space. our gpu claims 64-bit support in pci config space and the cpu is an em64t. but the customer is running a 32-bit kernel on the em64t, which is a reasonable thing to do. it turns out the pci driver does not like 64-bit bars on a 32-bit kernel and prints out the following messages during boot:
PCI: PCI BIOS revision 2.10 entry at 0xf0031, last bus=5 PCI: Using configuration type 1 PCI: Probing PCI hardware PCI: Probing PCI hardware (bus 00) PCI: Ignoring BAR0-3 of IDE controller 00:1f.1 PCI: Unable to handle 64-bit address space for PCI: Unable to handle 64-bit address space for PCI: Unable to handle 64-bit address for device 03:00.0 PCI: Unable to handle 64-bit address space for
Is this an expected problem? Is there any reason why the 32-bit kernel couldn't handle 64-bit bars?
here's what pci config space for our gpu looks like:
00: de 10 ce 00 07 01 10 00 a2 00 00 03 10 00 00 00 10: 00 00 00 de 0c 00 00 f8 0f 00 00 00 04 00 00 dd 20: 00 00 00 00 00 00 00 00 00 00 00 00 de 10 43 02 30: 00 00 ee df 60 00 00 00 00 00 00 00 0a 01 00 00
Thanks, Terence
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