From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751002AbZKEAEI (ORCPT ); Wed, 4 Nov 2009 19:04:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750791AbZKEAEH (ORCPT ); Wed, 4 Nov 2009 19:04:07 -0500 Received: from mail-yw0-f202.google.com ([209.85.211.202]:55763 "EHLO mail-yw0-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750789AbZKEAEG (ORCPT ); Wed, 4 Nov 2009 19:04:06 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; b=qcbGfTYeP8Dy8BKvtU/63SDBOzE8mxtzkTTsfEkGpbdGAh4PC5WnzTk/OxZQXIwMgz kpiuN/Ml6yfnXdy4S6pYY7zELRccCwY6zm0xIbU/syvdyFBe2Q2zDN1sKE5f75/RL+hQ O/aJFroEkZm7RoAwmeB1Xfew4ZgfZ7u4doen8= Message-ID: <4AF21678.5020107@gmail.com> Date: Wed, 04 Nov 2009 18:04:08 -0600 From: Robert Hancock User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.4pre) Gecko/20091014 Fedora/3.0-2.8.b4.fc11 Thunderbird/3.0b4 MIME-Version: 1.0 To: Valdis.Kletnieks@vt.edu CC: Justin Piszcz , linux-kernel@vger.kernel.org Subject: Re: Kernel Options: To use MSI-X or not? References: <14754.1257356211@turing-police.cc.vt.edu> In-Reply-To: <14754.1257356211@turing-police.cc.vt.edu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/04/2009 11:36 AM, Valdis.Kletnieks@vt.edu wrote: > On Wed, 04 Nov 2009 11:53:18 EST, Justin Piszcz said: > >> Example, 3ware cards/Intel Audio Drivers you can use MSI-X instead of >> having several devices use/share an interrupt. >> >> What are the pros/cons to using MSI-X vs. having devices share an IRQ? > > Cons: Sometimes, you'll find a device that claims to support MSI but in fact is > to some extent borked... > > I'm the proud owner of a Dell Latitude D820, which includes this PCI: > > 00:1b.0 Audio device: Intel Corporation 82801G (ICH7 Family) High Definition Audio Controller (rev 01) > Subsystem: Dell Device 01cc > Flags: bus master, fast devsel, latency 0, IRQ 30 > Memory at efffc000 (64-bit, non-prefetchable) [size=16K] > Capabilities: [50] Power Management version 2 > Capabilities: [60] MSI: Enable+ Count=1/1 Maskable- 64bit+ > Capabilities: [70] Express Root Complex Integrated Endpoint, MSI 00 > Capabilities: [100] Virtual Channel > Capabilities: [130] Root Complex Link > Kernel driver in use: HDA Intel > > However, actually trying to enable MSI gets me this at some pseudo-random > time after booting (one for each of 7 boots): > > [ 4.519264] ALSA sound/pci/hda/hda_intel.c:683: No response from codec, disabling MSI: last cmd=0x00df0900 > [ 22.788015] ALSA sound/pci/hda/hda_intel.c:683: No response from codec, disabling MSI: last cmd=0x008f0c00 > [ 4.719263] ALSA sound/pci/hda/hda_intel.c:683: No response from codec, disabling MSI: last cmd=0x00df0900 > [ 12.497263] ALSA sound/pci/hda/hda_intel.c:683: No response from codec, disabling MSI: last cmd=0x00df0900 > [ 815.350265] ALSA sound/pci/hda/hda_intel.c:683: No response from codec, disabling MSI: last cmd=0x00df0900 > [ 595.171267] ALSA sound/pci/hda/hda_intel.c:683: No response from codec, disabling MSI: last cmd=0x00171700 > [ 4.968263] ALSA sound/pci/hda/hda_intel.c:683: No response from codec, disabling MSI: last cmd=0x00df0900 > > (Am slightly mystified about the resets at 4 and 12 seconds - at that point, > we're not up far enough to actually try to use the audio. I suspect udev trying > to initialize the card - except sometimes it works and runs just fine with > MSI for quite some time: > > [14267.701267] ALSA sound/pci/hda/hda_intel.c:683: No response from codec, disabling MSI: last cmd=0x00df0900 > [12841.892050] ALSA sound/pci/hda/hda_intel.c:683: No response from codec, disabling MSI: last cmd=0x00df0900 > [10647.783274] ALSA sound/pci/hda/hda_intel.c:683: No response from codec, disabling MSI: last cmd=0x001f1500 > [15091.102034] ALSA sound/pci/hda/hda_intel.c:683: No response from codec, disabling MSI: last cmd=0x00171700 > [20085.955293] ALSA sound/pci/hda/hda_intel.c:683: No response from codec, disabling MSI: last cmd=0x00df0700 This may not be an actual MSI problem (in fact I'd say it's probably not). Currently hda_intel disables MSI after any codec response timeout, so it could be it would have worked if it retried while still using MSI. I believe Takashi was going to change the driver to be less sensitive about this.