Here is a dmesg log from september, running the PCI Nvidia 8400GS rev.2 with nouveau on a K8 non-AGP host with Nvidia C51 PCI Express bridge. The GPU is driven by proprietary non-free closed nvidia driver. Yet again, this PCI GPU is known to work with nvidia driver when plugged into an Intel platform. Here may be the interesting parts: ``` [ 76.927044] NVRM: GPU at PCI:0000:05:00: GPU-d18ccf5d-6557-e114-0ca8-23449bccf157 [ 76.927050] NVRM: Xid (PCI:0000:05:00): 6, PE0002 [ 78.018458] NVRM: Xid (PCI:0000:05:00): 8, Channel 00000001 [ 80.010804] NVRM: os_schedule: Attempted to yield the CPU while in atomic or interrupt context [ 82.017647] NVRM: os_schedule: Attempted to yield the CPU while in atomic or interrupt context [ 90.401898] NVRM: Xid (PCI:0000:05:00): 8, Channel 0000007e [ 92.385614] NVRM: os_schedule: Attempted to yield the CPU while in atomic or interrupt context [ 96.321610] NVRM: os_schedule: Attempted to yield the CPU while in atomic or interrupt context [ 106.785733] NVRM: Xid (PCI:0000:05:00): 8, Channel 0000007e [ 108.785676] NVRM: os_schedule: Attempted to yield the CPU while in atomic or interrupt context [ 112.785766] NVRM: os_schedule: Attempted to yield the CPU while in atomic or interrupt context [ 123.169763] NVRM: Xid (PCI:0000:05:00): 8, Channel 0000007e [ 125.153618] NVRM: os_schedule: Attempted to yield the CPU while in atomic or interrupt context [ 129.153612] NVRM: os_schedule: Attempted to yield the CPU while in atomic or interrupt context [ 138.079318] resource sanity check: requesting [mem 0x000c0000-0x000fffff], which spans more than pnp 00:06 [mem 0x000ce000-0x000cffff] [ 138.079726] caller os_map_kernel_space+0x6d/0xb0 [nvidia] mapping multiple BARs [ 145.569349] NVRM: GPU at PCI:0000:05:00: GPU-d18ccf5d-6557-e114-0ca8-23449bccf157 [ 145.569386] NVRM: Xid (PCI:0000:05:00): 6, PE0002 [ 146.689722] NVRM: Xid (PCI:0000:05:00): 8, Channel 00000001 [ 148.689670] NVRM: os_schedule: Attempted to yield the CPU while in atomic or interrupt context [ 150.690247] NVRM: os_schedule: Attempted to yield the CPU while in atomic or interrupt context [ 159.009723] NVRM: Xid (PCI:0000:05:00): 8, Channel 0000007e [ 161.009666] NVRM: os_schedule: Attempted to yield the CPU while in atomic or interrupt context [ 165.009757] NVRM: os_schedule: Attempted to yield the CPU while in atomic or interrupt context [ 175.393763] NVRM: Xid (PCI:0000:05:00): 8, Channel 0000007e [ 177.393696] NVRM: os_schedule: Attempted to yield the CPU while in atomic or interrupt context [ 181.393788] NVRM: os_schedule: Attempted to yield the CPU while in atomic or interrupt context [ 191.777761] NVRM: Xid (PCI:0000:05:00): 8, Channel 0000007e [ 193.505609] NVRM: os_schedule: Attempted to yield the CPU while in atomic or interrupt context [ 197.717628] NVRM: os_schedule: Attempted to yield the CPU while in atomic or interrupt context ``` Note that there is two things you can ignore from this log, this part: ``` [ 47.301362] NVRM: The NVIDIA GeForce 6150 LE GPU installed in this system is NVRM: supported through the NVIDIA 304.xx Legacy drivers. Please NVRM: visit http://www.nvidia.com/object/unix.html for more NVRM: information. The 340.108 NVIDIA driver will ignore NVRM: this GPU. Continuing probe... [ 47.301582] NVRM: ignoring the legacy GPU 0000:00:05.0 [ 47.302069] nvidia: probe of 0000:00:05.0 failed with error -1 ``` This motherboard features an onboard soldered Geforce 6150 LE GPU usually accessed through HyperTransport bus when there is no add-on card on PCIe slots. The BIOS is expected to disable the onboard GPU when there is an add-on one, and it usually disables that onboard GPU when there is an add-on one (usually on PCI Express port), except when this Nvidia PCI card is plugged. Anyway, the driver ignores it. The part that can be ignored is this one: ``` [ 55.661641] NVRM: Your system is not currently configured to drive a VGA console [ 55.661645] NVRM: on the primary VGA device. The NVIDIA Linux graphics driver [ 55.661646] NVRM: requires the use of a text-mode VGA console. Use of other console [ 55.661648] NVRM: drivers including, but not limited to, vesafb, may result in [ 55.661648] NVRM: corruption and stability problems, and is not supported. ``` It's a warning the proprietary non-free closed driver is printing to ask the user to plug an useless screen on the VGA port (that will not be able to display anything and will not be made available to the user to extend the desktop) so the user can use a screen on the DVI port properly. This is just an Nvidia weirdness among **many**, and this has nothing to do with the current bug, this weirdness can be experimented with select other Nvidias GPU including PCIe ones that work on this host and on others. The nouveau driver does not ask to plug the VGA to an useless screen to use the DVI port correctly, neither has this limitation since the nouveau driver can drives two screens at the same time using both VGA and DVI ports. This part in dmesg is just noise unrelated to our current problem. Since both nouveau and proprietary non-free closed nvidia driver fail we may assume the issue is in a common part of the kernel.