From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0BADDC433FE for ; Wed, 16 Mar 2022 11:52:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355500AbiCPLxf (ORCPT ); Wed, 16 Mar 2022 07:53:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37858 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355502AbiCPLx2 (ORCPT ); Wed, 16 Mar 2022 07:53:28 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C72EC65829; Wed, 16 Mar 2022 04:52:13 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 5D146616E3; Wed, 16 Mar 2022 11:52:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8C437C340E9; Wed, 16 Mar 2022 11:52:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1647431532; bh=YIXNbeLlceKzi8tGJMsF0FSZC0BtIxsHH/dOGJwT3vo=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=eKM0V6/6SZPbobuGuYihJZagDFL2cWeBBa6cb8AgOtGOyj28kepg59L6FR9shoG7B ggj9FT4PjlZwfKAAaphsQW5cJ34FqycaQ8ba6ZQuBmGBEdmzdN/JT9JEGX8QDe34nR 8ndPhY8OH7WXKUnnqLCqjt3FXbCfWe9b1vDmSvqcxHSST4MtFJwxGhVPMcyrBfHIY6 M5f3Hdkajmnwz+NksW+p9t8ngSZTku3YOgr1dbLSVALyITTGNx+fDYZVHgu+Z+wDyU /MYYpaBpGxSny2QRCT8NSIasxPg6iKWeWiFs/bTeBcvMJ6GTwiF9SgpdQyi/LWbMF/ Hz+Qt4RP/KzZg== Date: Wed, 16 Mar 2022 06:52:09 -0500 From: Bjorn Helgaas To: Andy Shevchenko Cc: Bjorn Helgaas , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, micklorain@protonmail.com Subject: Re: [PATCH v1 1/1] PCI: Enable INTx quirk for ATI PCIe-USB adapter Message-ID: <20220316115209.GA666450@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Wed, Mar 16, 2022 at 12:27:57PM +0200, Andy Shevchenko wrote: > On Tue, Mar 15, 2022 at 03:22:31PM -0500, Bjorn Helgaas wrote: > > On Tue, Mar 15, 2022 at 12:09:08PM +0200, Andy Shevchenko wrote: > > > On Mon, Mar 14, 2022 at 02:42:53PM -0500, Bjorn Helgaas wrote: > > > > On Mon, Mar 14, 2022 at 12:14:48PM +0200, Andy Shevchenko wrote: > > > > > ATI PCIe-USB adapter advertises MSI, but it doesn't work if INTx is disabled. > > > > > Enable the respective quirk as it's done for other ATI devices on this chipset, > > > > > > > > > > Fixes: 306c54d0edb6 ("usb: hcd: Try MSI interrupts on PCI devices") > > > > > > > > This is interesting because there must be a TON of these AMD/ATI SB600 > > > > USB devices in the field, and 306c54d0edb6 was merged in July 2020 and > > > > appeared in v5.9. > > > > > > > > So why would we only get a report now, in February 2022? Is there > > > > some change more recent than 306c54d0edb6 that exposed this problem? > > > > > > I think it's a rhetorical question. To me it's as simple as the latency > > > between getting the change into the kernel. > > > > > > However, I'm a bit worried that in case of ATI there are not so many > > > platforms that are kept up-to-dated. > > > > This would be a rhetorical question if I were not interested in the > > answer but asking only to make a point. That's not the case at all. > > > > If these SB600 USB devices stopped working in v5.9 (October 2020), > > that would affect lots of keyboards and mice, and I would be surprised > > if we didn't hear about it until February, 2022. > > > > I looked through https://github.com/linuxhw/Dmesg, and there are at > > least 40 dmesg logs from v5.9 or later with SB600 USB, so I'm > > still a little skeptical that 306c54d0edb6 by itself is enough to > > explain this. > > > > Anyway, I applied this to pci/msi for v5.18 with the following commit > > log: > > > > PCI: Disable broken MSI on ATI SB600 USB adapters > > > > Some ATI SB600 USB adapters advertise MSI, but MSI doesn't work if INTx is > > disabled. Disable MSI on these adapters. > > But IIUC MSI is _not_ disabled. That's why I have issued this version of the > patch with different commit message. Did I misunderstand something? Oh, right, of course. Sorry, I was asleep at the wheel. I guess it's just that for these devices, we don't disable INTx when enabling MSI. I can't remember why we disable INTx when enabling MSI, but it raises the question of whether it's better to leave INTx enabled or to just disable use of MSI completely. Bjorn