From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dominik Brodowski Subject: Re: Entering C3 Processor State without a Bus Arbiter Date: Fri, 16 Jan 2004 10:30:55 +0100 Sender: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Message-ID: <20040116093055.GE9814@dominikbrodowski.de> References: <20040115154555.V73140@root.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="Ycz6tD7Th1CMF4v7" Return-path: Content-Disposition: inline In-Reply-To: <20040115154555.V73140-Y6VGUYTwhu0@public.gmane.org> Errors-To: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: Nate Lawson Cc: Dino Klein , acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: linux-acpi@vger.kernel.org --Ycz6tD7Th1CMF4v7 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jan 15, 2004 at 03:52:12PM -0800, Nate Lawson wrote: > > After removing the restrictions in the source files, and adding a WBINVD > > instruction right before the read from P_LVL3 - the processor was put in > > the C3 state. This is on my Via Apollo Pro133A based Abit VP6 board, > > which does not have a Bus Arbiter. Just for the record, I did pull out > > the second CPU, so I can do "safer" experimentation. >=20 > WBINVD is too expensive when you're entering C3 hundreds of times per > second. Try playing back an mp3 while dd'ing a CDROM in PIO mode to your > hard drive. Goodbye data, hello backups! The CPU can't snoop the bus in > C3. You shouldn't enter C3 at all when the CPU is woken up hundreds of times per second. Maximum allowed latency is 1ms, IIRC -- you really shouldn't get into this state while dd'ing a CDROM or something else... Problem is, WBINVD might take even longer than 1ms, even though the maximum I got on my PIII notebook was about 900us... Dominik --Ycz6tD7Th1CMF4v7 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (GNU/Linux) iD8DBQFAB69PZ8MDCHJbN8YRAsZdAKCIlss/t+sgGDlLSC2JlFzq1lX6PwCfXyMG u28XLLzEGSOlypMPNXxiXR4= =wFLG -----END PGP SIGNATURE----- --Ycz6tD7Th1CMF4v7-- ------------------------------------------------------- The SF.Net email is sponsored by EclipseCon 2004 Premiere Conference on Open Tools Development and Integration See the breadth of Eclipse activity. February 3-5 in Anaheim, CA. http://www.eclipsecon.org/osdn