From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751838AbWAERAA (ORCPT ); Thu, 5 Jan 2006 12:00:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751843AbWAEQ77 (ORCPT ); Thu, 5 Jan 2006 11:59:59 -0500 Received: from ms-smtp-02.nyroc.rr.com ([24.24.2.56]:30870 "EHLO ms-smtp-02.nyroc.rr.com") by vger.kernel.org with ESMTP id S1751838AbWAEQ76 (ORCPT ); Thu, 5 Jan 2006 11:59:58 -0500 Subject: Re: Apparent problems with interrupt latency with PCI2PCI bridges (register_serial(): autoconfig failed) From: "Michael R. Head" To: Linux Kernel Mailing List In-Reply-To: <1136398726.31979.29.camel@phoenix> References: <1136398726.31979.29.camel@phoenix> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-MYSyoXUwky5Ho5cLE2NO" Organization: GPG: http://www.suppressingfire.org/~burner/gpg.key.txt [0x4C9DA1D0] Date: Thu, 05 Jan 2006 11:59:14 -0500 Message-Id: <1136480354.9411.26.camel@phoenix> Mime-Version: 1.0 X-Mailer: Evolution 2.4.1 X-Scanner: exiscan *1EuYSn-0000lo-00*Sb/REFI4K4o* Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --=-MYSyoXUwky5Ho5cLE2NO Content-Type: text/plain Content-Transfer-Encoding: quoted-printable In case anyone else ends up with this problem, here's how it's resolving...=20 I've been told that this is a result of PCI interface controller on the card (a PLX PCI9050) having trouble with PCI bridges. All of the cards that I have been having trouble with use this interface controller, so that seems to explain my problems. On Wed, 2006-01-04 at 13:18 -0500, Michael R. Head wrote: > Hello, I'm having some trouble with a number of PCI cards and several > PCI bridges. In order to reduce the problem, I'm going to ask about 1 > specific card and one specific bridge. >=20 > The hardware I'm working with is a P4 2.4Ghz machine in a 4U rackmount > chassis. On board are 3 PCI slots connected to the main PCI bus and 9 > PCI slots connected to a bridge to the main PCI bus. >=20 > The software I'm running is an up to date RHEL3 (kernel 2.4.21-37.EL), > but I experience the same problems when I boot off an Ubuntu Breezy > LiveCD (which uses 2.6.12). >=20 > I have an 8 port RS232 card using 16550A UARTs (Sealevel Systems Inc > Eight Port RS-232 Interface). When I plug it into the main PCI bus (#2), > it works perfectly and I get ttyS4-11 working automatically and > properly. >=20 > However, when I put the card in a PCI slot on bus #3 (which is on the > other side of a Pericom Semiconductor PCI to PCI Bridge), I see this > during boot: >=20 > $ dmesg | grep -2 serial > ttyS3 at 0x02e8 (irq =3D 3) is 16550A > register_serial(): autoconfig failed > Real Time Clock Driver v1.10e >=20 >=20 > When I plug it into a slot on bus #2, I get this from setserial: > $ setserial -g /dev/ttyS4 > /dev/ttyS4, UART: 16550A, Port 0xd200, IRQ: 2 >=20 > When I plut the card into a slot on bus #3, setserial tells me this (by > default); > $ setserial -g /dev/ttyS4 > /dev/ttyS4, UART: unknown, Port: 0xc100, IRQ: 2 >=20 > If I attempt to reconfigure ttyS4 to have the settings from above, I get > the dreaded "ttyS4: LSR safety check engaged!" and from then on, any > access to /dev/ttyS4 results in "/dev/ttyS4: No such device". >=20 >=20 >=20 > Now, I also have some other PCI cards that are having trouble with > living on the other side of a PCI bridge, but their drivers are > available separately from the kernel. I figure that if I can get the > serial card working, then hopefully the rest will work, too. >=20 > I also have an external 4U rackmount chassis containing 12 additional > PCI slots that are connected via 4 Intel 21142 PCI-to-PCI bridges, and > when I connect the serial card into any of those busses, I get the same > problem. >=20 >=20 > I've tried fiddling with all sorts of kernel PCI options at boot and > fiddling with various setpci commands. Nothing seems to help. Any > suggestions or information would be greatly appreciated. >=20 > thanks, > mike >=20 --=20 Michael R. Head GPG: http://www.suppressingfire.org/~burner/gpg.key.txt [0x4C9DA1D0] --=-MYSyoXUwky5Ho5cLE2NO Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (GNU/Linux) iD8DBQBDvVBiNXGzGEydodARAiumAJwKuU4Q4jApI4xyGGoh4+g5vw5Z/QCgk8gm NcjHMmiXffeV4gOeVEljn0M= =Lsvh -----END PGP SIGNATURE----- --=-MYSyoXUwky5Ho5cLE2NO--