From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bmailout2.hostsharing.net (bmailout2.hostsharing.net [83.223.78.240]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id ECCDA1C5496; Fri, 28 Feb 2025 07:14:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=83.223.78.240 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740726856; cv=none; b=NlwlTWKSKa22Iq6n3UvB0Z7/E/hxMLX8i0OHvDLjCdypFfbbDBI/PNzwVLZRt3rVkSwFQGEp2y6s5BmkJoO42Tx0gM5/6R7jeJ5hA3nWvZ5TjuLAYp4phQcXRt1+kaQ+uPEvZiR436yqeJDLhM4yMjK4llfaFD1ya/OyQZXIsug= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740726856; c=relaxed/simple; bh=StuzEqVA/KF2H1BBO4p86yNKqTmdpTRhdbvVEeXDUNs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=SQ/wdvvh0Lh5+BA/TuXKEs+gRyXXX+DOZgO7ee/oIVBCJC3x0OzCAb+k2s2ZQ1iHNPE9W7YdTQ1A3Ir9gHWBnrJ261QnTiVLzTaJX5Jk1CqvXg01GDY3tSUUKPQcoZlnIrTVyn6D7wW/EmGkU6pPgR79OdP4aWrq1CNR7xen4p4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=wunner.de; spf=none smtp.mailfrom=h08.hostsharing.net; arc=none smtp.client-ip=83.223.78.240 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=wunner.de Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=h08.hostsharing.net Received: from h08.hostsharing.net (h08.hostsharing.net [83.223.95.28]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "*.hostsharing.net", Issuer "RapidSSL TLS RSA CA G1" (verified OK)) by bmailout2.hostsharing.net (Postfix) with ESMTPS id 975BD280237A3; Fri, 28 Feb 2025 08:14:04 +0100 (CET) Received: by h08.hostsharing.net (Postfix, from userid 100393) id 7EFEE6501C4; Fri, 28 Feb 2025 08:14:04 +0100 (CET) Date: Fri, 28 Feb 2025 08:14:04 +0100 From: Lukas Wunner To: Feng Tang Cc: rafael@kernel.org, Bjorn Helgaas , Sathyanarayanan Kuppuswamy , Liguang Zhang , Guanghui Feng , Markus Elfring , lkp@intel.com, Jonathan Cameron , ilpo.jarvinen@linux.intel.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 2/4] PCI/portdrv: Add necessary wait for disabling hotplug events Message-ID: References: <20250224034500.23024-1-feng.tang@linux.alibaba.com> <20250224034500.23024-3-feng.tang@linux.alibaba.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Fri, Feb 28, 2025 at 02:29:29PM +0800, Feng Tang wrote: > On Tue, Feb 25, 2025 at 12:42:04PM +0800, Feng Tang wrote: > > > > There might be some misunderstaning here :), I responded in > > > > https://lore.kernel.org/lkml/Z6LRAozZm1UfgjqT@U-2FWC9VHC-2323.local/ > > > > that your suggestion could solve our issue. > > > > > > Well, could you test it please? > > > We just tried the patch on the hardware and initial 5.10 kernel, and > the problem cannot be reproduced, as the first PCIe hotplug command > of disabling CCIE and HPIE was not issued. Good! > Should I post a new version patch with your suggestion? Yes, please. > Also I would like to separate this patch from the patch dealing the > nomsi irq storm issue. How do you think? Makes sense to me. The problem with the nomsi irq storm is really that if the platform (i.e. BIOS) doesn't grant OSPM control of hotplug, OSPM (i.e. the kernel) cannot modify hotplug registers because the assumption is that the platform controls them. If the platform doesn't actually handle hotplug, but keeps the interrupts enabled, that's basically a bug of the specific platform. I think the kernel community's stance in such situations is that the BIOS vendor should provide an update with a fix. In some cases that's not posible because the product is no longer supported, or the vendor doesn't care about Linux issues because it only supports Windows or macOS. In those cases, we deal with these problems with a quirk. E.g. on x86 we often use a DMI quirk to recognize affected hardware and the quirk would then disable the hotplug interrupts. Thanks, Lukas