From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754713AbXD1GK3 (ORCPT ); Sat, 28 Apr 2007 02:10:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754704AbXD1GK3 (ORCPT ); Sat, 28 Apr 2007 02:10:29 -0400 Received: from nz-out-0506.google.com ([64.233.162.229]:45109 "EHLO nz-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754705AbXD1GKO (ORCPT ); Sat, 28 Apr 2007 02:10:14 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:date:from:to:cc:subject:message-id:in-reply-to:references:x-mailer:mime-version:content-type; b=e7TjiClujIsI7krlT6VAedpsTwiKdGrlKdNL2reVRkfIPwwtpgF58I+j8Yq0YQIJfiLM63KfR7h0DKYS1Hh5gRgWga5zjuLob3wt0F8HemI2v4/M5YYiLA29/3dsI64/i4GMyFIDPIGUm9zdv1qE5zcI5bBsl/VN2oRYMph2kQQ= Date: Fri, 27 Apr 2007 23:09:50 -0700 From: Mike Mattie To: Sergei Shtylyov Cc: lkml Subject: Re: htpt366 PCI latency value is really high Message-ID: <20070427230950.33d4d040@reforged> In-Reply-To: <4630B789.3040402@ru.mvista.com> References: <20070426064927.13d0ed72@reforged> <4630B789.3040402@ru.mvista.com> X-Mailer: Claws Mail 2.6.1 (GTK+ 2.10.9; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: multipart/signed; boundary=Sig_v_WEieGHBbHJStsP_ftKiz3; protocol="application/pgp-signature"; micalg=PGP-SHA1 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --Sig_v_WEieGHBbHJStsP_ftKiz3 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Thu, 26 Apr 2007 18:30:33 +0400 Sergei Shtylyov wrote: > Hello. >=20 > Mike Mattie wrote: >=20 > > while hunting down some latency problems I found something quite > > odd. The latency reported by lspci -v for the HTP203N card is > > enormous. >=20 > > 00:09.0 RAID bus controller: Triones Technologies, Inc. HPT302/302N > > (rev 02) Subsystem: Triones Technologies, Inc. Unknown device 0001 > > Flags: bus master, 66MHz, medium devsel, latency 120, IRQ 17 > > I/O ports at ec00 [size=3D8] > > I/O ports at e800 [size=3D4] > > I/O ports at e400 [size=3D8] > > I/O ports at e000 [size=3D4] > > I/O ports at dc00 [size=3D256] > > Expansion ROM at dffe0000 [disabled by cmd] [size=3D128K] > > Capabilities: [60] Power Management version 2 >=20 > > I am assuming that the "latency" field here is the PCI latency timer > > which means this card is a bus hog.=20 >=20 > > From some reading on this issue linux methodically sets a sane > > value for all the PCI cards it sets up, which looks normal on the > > rest of the system, which is set to the value: 32 >=20 > Hm, I'm only seeing clamping to the smallest of 64 and > pcibios_max_latency (255) in arch/i386/pci/i386.c if the latency > value is too low... Which arch are you using? >=20 > > setting the value 32 with: >=20 > > setpci -v -s "00:09.0" latency_timer=3D32 >=20 > > 00:09.0 RAID bus controller: Triones Technologies, Inc. HPT302/302N > > (rev 02) Subsystem: Triones Technologies, Inc. Unknown device 0001 > > Flags: bus master, 66MHz, medium devsel, latency 48, IRQ 17 > > I/O ports at ec00 [size=3D8] > > I/O ports at e800 [size=3D4] > > I/O ports at e400 [size=3D8] > > I/O ports at e000 [size=3D4] > > I/O ports at dc00 [size=3D256] > > Expansion ROM at dffe0000 [disabled by cmd] [size=3D128K] > > Capabilities: [60] Power Management version 2 >=20 > > Results in 48, which is not what I asked, but hopefully this is > > linux doing the right thing. output is decimal, input is hex - self-rtfm. =20 > Not sure -- seems likely that it's the chip's own enforced minimum > instead... >=20 > > I know this chipset is pretty brain-damaged, but is this > > high latency value a work-around for broken hardware, or >=20 > More like it. Although HighPoint's own drivers force 64. >=20 > > just a oversight ? >=20 > Not likely since the value is too "special"... I have ran with a setting of 40 for a couple of days without any trouble. There are many reasons a card would default to a higher level, but in the end it is basically tuning the card for a server application. A warning that some cards default to high PCI latency values; settings that= =20 can interfere with latency sensitive devices such as sounds cards - this=20 could be a help to others. =20 00:09.0 RAID bus controller: Triones Technologies, Inc. HPT302/302N (rev 02) Subsystem: Triones Technologies, Inc. Unknown device 0001 Flags: bus master, 66MHz, medium devsel, latency 40, IRQ 19 I/O ports at ec00 [size=3D8] I/O ports at e800 [size=3D4] I/O ports at e400 [size=3D8] I/O ports at e000 [size=3D4] I/O ports at dc00 [size=3D256] Expansion ROM at dffe0000 [disabled by cmd] [size=3D128K] Capabilities: [60] Power Management version 2 > > Cheers, > > Mike Mattie - codermattie@gmail.com >=20 > WBR, Sergei --Sig_v_WEieGHBbHJStsP_ftKiz3 Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQFGMuU0dfRchrkBInkRAnTvAKCaBWAWAdih72K8mBb8biPgOlvjhgCdF3C3 TYOv5eNrXVIqIew2VkLMT4w= =PoR3 -----END PGP SIGNATURE----- --Sig_v_WEieGHBbHJStsP_ftKiz3--