From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dominik Brodowski Subject: Re: powernow-k8 updates Date: Fri, 26 Mar 2004 14:02:54 +0100 Sender: cpufreq-bounces@www.linux.org.uk Message-ID: <20040326130254.GA9284@dominikbrodowski.de> References: <20040326120151.GA3102@elf.ucw.cz> <20040326121915.GA207@elf.ucw.cz> <20040326122742.GA8871@dominikbrodowski.de> <20040326123216.GB321@elf.ucw.cz> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============2135971828==" Return-path: In-Reply-To: <20040326123216.GB321@elf.ucw.cz> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: cpufreq-bounces+glkc-cpufreq=gmane.org@www.linux.org.uk To: Pavel Machek Cc: paul.devriendt@amd.com, Cpufreq mailing list --===============2135971828== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="azLHFNyN32YCQGCU" Content-Disposition: inline --azLHFNyN32YCQGCU Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Mar 26, 2004 at 01:32:16PM +0100, Pavel Machek wrote: > On P=E1 26-03-04 13:27:42, Dominik Brodowski wrote: > > On Fri, Mar 26, 2004 at 01:19:15PM +0100, Pavel Machek wrote: > > > Hi! > > >=20 > > > > Few updates, enable ACPI, add common printing function, fix typo, m= ove > > > > "pst out of sequence" where it belongs, fix formating in > > > > powernow-k8.h. I'm not quite sure what this is against, so this is > > > > "eyes only". > > >=20 > > > Its strange, ACPI code does not seem to mention batps at all, still > > > cpu goes to 800MHz when I unplug the cord... Perhaps it should at > > > least say something into the syslog? > >=20 > > ... again our differences about verbosity... :-) >=20 > Actually, I do not understand how it works. How does cpufreq know how > many states are there on battery? It does something, but I'd like to > understand it... The BIOS notifies the acpi processor module of a platform limit change (acpi_processor_notify). The acpi processor module then reads out the _PDC value of the ACPI table, which contains the maximum current supported P-State [P0 is highest freq, Px is lowest].=20 Then the cpufreq_update_policy() function is called: the last cpufreq policy set is send to the cpufreq notifiers, among them is acpi_processor_ppc_notifier(), which limits the max allowed frequency, see cpufreq_verify_within_limits(policy, 0, pr->performance->states[ppc].core_frequency * 1000); Then the policy (min/max frequency) is passed to a cpufreq governor [in mos= t=20 cases the userspace governor], which selects one speed between min and max= =20 frequency and tells the driver via ->target() of the frequency to set. Hope this clarifies, Dominik --azLHFNyN32YCQGCU Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (GNU/Linux) iD8DBQFAZCn+Z8MDCHJbN8YRAtIGAJ97gVf/AnjF5l0XCx9BfvrLtNS2VgCffR1u 2TcOhVYUzbD64L1G0chZAN4= =JkKK -----END PGP SIGNATURE----- --azLHFNyN32YCQGCU-- --===============2135971828== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Cpufreq mailing list Cpufreq@www.linux.org.uk http://www.linux.org.uk/mailman/listinfo/cpufreq --===============2135971828==--