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 1A7FD156F5E; Fri, 13 Jun 2025 13:52:50 +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=1749822774; cv=none; b=Ok3J17SDVAdo1rO+NuVE9lNo4Hhphxfqzp3nYlAjqIqD5/ewltmCTn2Jmp+q4lh4J0o04+xj4U0lQaYZLibQUa7lfJXRsh2mzOcN+da1WJPmw/9FceLRE0J2enT82go1QDCqbFZWFxCG3tHwmX2C8c8MrrU0XzGcIdnM1//AuMU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749822774; c=relaxed/simple; bh=cWb5O919iJ5GUz1RPBsizB20JDHxE/ASBUV9zv+N5lQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=dcRnjrc7AdI/QdB/w/nssfAoHCTjIVd0hYD72f+fq75DkbSJVjVhZZBOodUeybgVmSqavlXg+gfZLOHnm+ZhV+UM2OtyNBvZj3YiSIgRLWU93+/qsjSo1wWcG/YIlLktVBrROCeXS5Gax92tPEKeUa36wiSxGgbV7OeDL8W5Oxo= 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 0866620091AE; Fri, 13 Jun 2025 15:45:36 +0200 (CEST) Received: by h08.hostsharing.net (Postfix, from userid 100393) id E75D669ABA; Fri, 13 Jun 2025 15:45:35 +0200 (CEST) Date: Fri, 13 Jun 2025 15:45:35 +0200 From: Lukas Wunner To: Manivannan Sadhasivam Cc: grwhyte@linux.microsoft.com, linux-pci@vger.kernel.org, shyamsaini@linux.microsoft.com, code@tyhicks.com, Okaya@kernel.org, bhelgaas@google.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 0/2] PCI: Reduce FLR delay to 10ms for MSFT devices Message-ID: References: <20250611000552.1989795-1-grwhyte@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-pci@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, Jun 13, 2025 at 05:12:48PM +0530, Manivannan Sadhasivam wrote: > On Wed, Jun 11, 2025 at 12:05:50AM +0000, grwhyte@linux.microsoft.com wrote: > > Add a new flr_delay member of the pci_dev struct to allow customization of > > the delay after FLR for devices that do not support immediate readiness > > or readiness time reporting. The main scenario this addresses is VF > > removal and rescan during runtime repairs and driver updates, which, > > if fixed to 100ms, introduces significant delays across multiple VFs. > > These delays are unnecessary for devices that complete the FLR well > > within this timeframe. > > > > I don't think it is acceptable to *reduce* the standard delay just > because your device completes it more quickly. Proper way to reduce > the timing would be to support FRS as you said, but we cannot have > arbitrary delays for random devices. To be fair, we already have that for certain devices: The quirk delay_250ms_after_flr() is referenced by three different Vendor ID / Device ID combos and *lengthens* the delay after FLR. It's probably difficult to justify rejecting custom delays for certain MANA devices, even though we allowed them for three other devices. The proposed patch introduces a generic solution which avoids further cluttering up pci_dev_reset_methods[] with extra entries, so I think it's an approach worth considering. There are a bunch of nits in the proposed patches, such as "pci" not being capitalized, but the general approach seems fine to me. Thanks, Lukas