http://bugzilla.kernel.org/show_bug.cgi?id=6519
------- Additional Comments From [EMAIL PROTECTED] 2006-05-15 11:48 ------- On Mon, 15 May 2006, Andrew Morton wrote: > > @@ -873,7 +866,8 @@ static int acpi_processor_get_power_info > > for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) { > > if (pr->power.states[i].valid) { > > pr->power.count = i; > > - pr->flags.power = 1; > > + if (pr->power.states[i].type >= ACPI_STATE_C2) > > + pr->flags.power = 1; > > } > > } > > > > --------8<-------- > > > > The last change in the diff, in acpi_processor_get_power_info, is what > > makes the > > difference: commenting out the "if (pr->power.states[i].type >= > > ACPI_STATE_C2)" > > restores the power saving in 2.6.16.14 . That last change is also the thing that fixed the lock-up for Maneesh. We had this particular discussion at some point earlier, and didn't get to any resolution. The ACPI people wanted to undo the thing, which didn't make a lot of sense because (a) the comment says otherwise and (b) C1 is available even without ACPI and (c) nobody ever explained why it locked up without the "type >= ACPI_STATE_C2" test. Now, what happens is that your ACPI tables show that C2+ is unusable, which leaves only C1 usable (that, btw, you might be able to fix with different tables - possibly through a BIOS update). However, at that point it's totally pointless to even _try_ to use ACPI CPU power management for this case, since ACPI can't do any better than the normal C1 stuff in the bog-standard non-ACPI x86 idle routine. Do you actally see anything running hotter? Or is it just that the "CPU%d (power states:..)" message disappeared? Please realize that we will _always_ use C1 (aka "halt") in the idle state quite regardless of ACPI - unless you've done "idle=poll" on the kernel command line. So the fact that we don't use ACPI for it shouldn't make us actually run any hotter (quite the reverse - we'll go into C1 state with _less_ work). So I don't see the downside. Am I missing something? Linus ------- You are receiving this mail because: ------- You are on the CC list for the bug, or are watching someone who is. ------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ acpi-bugzilla mailing list acpi-bugzilla@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/acpi-bugzilla