Hello, I emailed a while back for some pointers on debugging a PCI problem and wanted to ask again for feedback. I was tracking an issue at: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1009312, where my Nvidia 8400M GT [10de:0426], on a Sony VGN-FZ260E, fails to initialize when the kernel loads, before the video driver even becomes an issue. I thought it might be a timeout issue, but now I'm thinking that something is accidentally shutting down the GPU even earlier than link retraining. I can confirm the problem's still there in v3.17-rc2 of the x86 kernel. Recently, through some more googling and debugging, I've figured out that passing the "pci=bios" kernel parameter gets the GPU to activate. So I can easily treat the problem for myself now, but I'd like to help wrap up anything related to an underlying cause. Also, with the "pci=earlydump" parameter and an init-script (at priority S98) for running lspci, I've found that something is altering parts of the PCI config space when the GPU fails. I've included trimmed copies of the PCIe config space from those two tests (0000:00:01.0 is the bridge in front of the GPU). While a lot of the changes seem to just reflect the GPU being off in the status registers, several other registers get wiped to zero: 1. The SERR driver is disabled in the command register 2. Both cache line size and the subsystem pci id are zeroed out 3. The interrupt line (but not the interrupt pin) goes from 05 to 00 4. The actual memory addresses in the BARs are cleared, but not the flags like prefetchable or 64-bit. What's more suspicious to me is the data between the standard config space and the first extended capability structure (at 0x60). The subsystem id is repeated at 0x40, plus a flag of some sort at 0x50, both of which are wiped to zero when the GPU fails to load. There's also a single digit at 0x54 and some data at 0x58-0x60 that remain in any case. I've tried studying the ACPI tables some too, but I'm not experienced with ASL so it doesn't mean much that nothing stood out to me. I narrowed things down to the DSDT because that seems to be where all the action is. Outside of some OSI conditionals and events, the other possibility that popped into my head is that somehow an ACPI mutex and a kernel lock are colliding. If anyone is interested, I can send a copy of the DSDT or any other disassembled tables to the list. Beyond general ideas and advice about the DSDT, I'm wondering if (or where) the kernel code is wiping these PCI config values, or if the zeros are all just from the GPU going into hibernation. I've tried a lot of grepping for variations of pci_write_config calls but haven't found anything yet. Also, if this is ultimately an issue with the GPU, how much could I even help with that? I've practiced dumping a video BIOS but have no clue how to analyze it. Thanks in advance, Kyle Auble
pci 0000:00:01.0 config space: 00: 86 80 01 2a 07 01 10 00 0c 00 04 06 10 00 01 00 10: 00 00 00 00 00 00 00 00 00 01 01 00 20 20 00 00 20: 00 cc f0 ce 01 d0 f1 df 00 00 00 00 00 00 00 00 30: 00 00 00 00 88 00 00 00 00 00 00 00 05 01 1a 00 40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 80: 01 90 03 c8 00 00 00 00 0d 80 00 00 4d 10 05 90 90: 05 a0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 a0: 10 00 41 01 00 80 00 00 00 00 00 00 01 2d 01 02 b0: 43 00 01 11 c0 25 0c 00 c0 01 48 00 00 00 00 00 c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 pci 0000:01:00.0 config space: 00: de 10 26 04 07 01 10 00 a1 00 00 03 10 00 00 00 10: 00 00 00 ce 0c 00 00 d0 00 00 00 00 04 00 00 cc 20: 00 00 00 00 01 20 00 00 00 00 00 00 4d 10 05 90 30: 00 00 00 00 60 00 00 00 00 00 00 00 05 01 00 00 40: 4d 10 05 90 00 00 00 00 00 00 00 00 00 00 00 00 50: 01 00 00 00 01 00 00 00 ce d6 23 00 00 00 00 00 60: 01 68 02 00 00 00 00 00 05 78 80 00 00 00 00 00 70: 00 00 00 00 00 00 00 00 10 00 01 00 e0 84 2c 01 80: 10 28 00 00 01 3d 01 00 4b 00 01 11 00 00 00 00 90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
pci 0000:00:01.0 config space: 00: 86 80 01 2a 07 05 10 00 0c 00 04 06 10 00 01 00 10: 00 00 00 00 00 00 00 00 00 01 01 00 20 20 00 20 20: 00 cc f0 ce 01 d0 f1 df 00 00 00 00 00 00 00 00 30: 00 00 00 00 88 00 00 00 00 00 00 00 05 01 1a 00 40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 80: 01 90 03 c8 00 00 00 00 0d 80 00 00 4d 10 05 90 90: 05 a0 01 00 0c 30 e0 fe 69 41 00 00 00 00 00 00 a0: 10 00 41 01 00 80 00 00 00 00 00 00 01 2d 01 02 b0: 43 00 01 11 c0 25 0c 00 c0 01 48 00 00 00 00 00 c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f0: 00 00 01 84 0c 00 00 a0 90 0f 04 00 31 00 00 00 pci 0000:01:00.0 config space: 00: de 10 26 04 03 00 10 00 a1 00 00 03 00 00 00 00 10: 00 00 00 00 0c 00 00 00 00 00 00 00 04 00 00 00 20: 00 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00 30: 00 00 00 00 60 00 00 00 00 00 00 00 00 01 00 00 40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 50: 00 00 00 00 01 00 00 00 ce d6 23 00 00 00 00 00 60: 01 68 02 00 00 00 00 00 05 78 80 00 00 00 00 00 70: 00 00 00 00 00 00 00 00 10 00 01 00 e0 84 2c 01 80: 10 28 0a 00 01 3d 01 00 08 00 01 11 00 00 00 00 90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
