From mboxrd@z Thu Jan 1 00:00:00 1970 From: Carsten Schiers Subject: AW: RE: RE: RE: No C-States any longer... Date: Thu, 16 Jun 2011 08:47:53 +0200 Message-ID: <27407493.491308206873767.JavaMail.root@uhura> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Return-path: Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: "Tian, Kevin" , xen-devel List-Id: xen-devel@lists.xenproject.org Maybe a dump question, but in the beginning of our discussion, we had: >> In drivers/scpi/processor_idle.c: ... >> On a working Intel machine, it will go through it like this: >> >> - acpi_processor_get_power_info_cst, which returns 0 >> - acpi_processor_get_power_info_default >> - later acpi_processor_power_verify will find some c-states > >this is expected sequence > >> >> On my non-working AMD machine, it will go through like this: >> - acpi_processor_get_power_info_cst, which returns -ENODEV >> - acpi_processor_get_power_info_fadt, which also return -ENODEV >> - this result is returned There is a comment in acpi_processor_get_power_info_default it is said that all processors need to support C1 at least. So (hypothesis), if my BIOS is not implemented as specified (neither _CST nor PBLK), shouldn't acpi_processor_get_power_info_default also bee called on my machine? Is the code exiting too early? Carsten.