Comment 21 for bug 1065840

Just in case it might help someone else, here's a wrapup of the final status for my issues.

Intent : migrate from "Ubuntu Studio x64 10.10" to "Ubuntu Studio x64 12.10" (both installed, on distinct HDDs)

System specs : Tyan s2915 (non-E) motherboard, Tyan BIOS v3.00, MCP55 Pro chipset, dual Opteron 2212, NUMA + IOMMU + S3 S-state + C2/C3 C-states are enabled, cross-nodes RAM interleave + NVRAID are disabled, NVidia 9600GT PCIe, SiliconImage 3124 eSATA controller PCI-X, 4xSATA II Hitachi HDDs

From info I've gathered here and there while searching for a solution, there seems to be two main "families" of suspend to RAM issues on NVidia chipsets :

  1- suspend procedure hangs because some devices refuse to suspend => machine wakes back up after ~30 seconds timeout

  2- suspend procedure finishes normally but some device concurrently wakes machine up (this behavior sometimes only occurs randomly, depending upon specific hardware) => machine's back up immediately

I experienced both problems above.
Here's what I believe were their root causes, with the workarounds (numbering corresponds to that of issue above) :

  1- kernel 3.5 differs from my previous kernel 2.6 by using by default, an async device-suspend scheme, which revealed an async-suspend-request management bug in NVidia's chipset driver (sata_nv), diag'ed in kernel bug #48951 opened by Joe Sapp (poster in this thread)

    => only workaround at the moment : use udev rule given in kernel bug #48951 thread, comment #20

  2- kernel 3.5 also differs from my previous kernel 2.6 by granting by default, USB devices the right to wake machine up from suspend (/proc/acpi/wakeup)

    => most frequently described workaround : unload driver of offending device before suspending (see for example : https://wiki.archlinux.org/index.php/Pm-utils#Standby_.2F_Suspend_to_RAM)

    => a workaround that I find less "invasive" : disable wake-up "permission" for offending devices before suspending, by means of a pm-utils hook (see : http://askubuntu.com/questions/152403/how-do-i-make-changes-to-proc-acpi-wakeup-permanent)

Hope it can help.
Eric