I had just disabled the AC driver, yeah, got similar backtrace from acpi video driver. Ok, enough, pattern is visible. The common point is that all backtraces lead to acpi_ex_acquire_global_lock According to sources, it is only taken on access to ACPI hardware ranges that are marked as 'Lock'. On my system only EC space is marked as such, thus this leads me to two conclusions. Ether during suspend EC access isn't synced (this is, EC transaction is still pending),or that EC gets busted (suprise...) on resume or suspend, and first read/write cycle to/from it never finishes. I am using hibernate cycles using 'reboot' mechanism. Best regards, Maxim Levitsky -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html