Bug#623088: Upgrade to kernel seems to resolve problem
I noticed that under Squeeze this error message appeared every time I booted.
May 5 21:22:07 debian kernel: [ 7.222495] ACPI: resource 0000:00:1f.3 [io 0x1c00-0x1c1f] conflicts with ACPI region SMBI [io 0x1c00-0x1c0f]
I have updated to Wheezy kernel and this message no longer appears. The bug also seems to have disappeared. No log file flooding and system degrading, and no problems (so far) with rebooting, hibernating or sleeping.