From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 2859820FA86 for ; Wed, 11 Jun 2025 16:40:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749660014; cv=none; b=pO6mPUO3cPcFu7ZcUJ09GztMmZn/llCArjloZjLDOdf/b/RN6o8HtbFSd/njNPio9TGdYPo9GCD4V8ZJorkwW08VqxZxfxM2sB0nM57kuqFSW1WKmj4HruWAb13gOa3ZqYS/ZI06cMxJxbifkRPyYteuUQA42+mzxXgj2cLJnA4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749660014; c=relaxed/simple; bh=l+mxvvSJje3rc/DPsMuR4oUJwj6tIwV3YLlupNT2q8Y=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Rps9Alw1AcS8BNJCuCj7la3JWg0T12BMySvpBm+gm/LCtxa+TnjFNCG89y+XnSpB8T538KMCMfBZgwRRNoHJMKRDy1FaJ07o/hR6AX7Xc/iixBre2vTXRLTPlwZlzmLKZmo2RfRHdEpCe6h7x+f6N2qQO0GcisYEGGLdRQuPvW8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=P+5vncWg; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="P+5vncWg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B0DA6C4CEE3; Wed, 11 Jun 2025 16:40:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1749660013; bh=l+mxvvSJje3rc/DPsMuR4oUJwj6tIwV3YLlupNT2q8Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=P+5vncWgNfib6yxkAr1RxTaTjnMuqitybv2gULgmuHIbiIBIUgEXxsV00uheNo2HJ QbNY9PIcZAR6DazSrJN3pvNlD6sgvDZl7Fp/PdiBYScy3HjsUUEziKtOymJFwO9jU8 dsY5C478XZ2HAto2KPkkEOv8ne/8klqAJ2Ra6JeJdI/PkL26QfyIP/3xMj1psOmFj2 WArqJgMAewIuSKIJlDesNTIhLAtHKguUzOZPB1qorRPJmt7QzTxCFmbINvDgtQ83r/ AKiMtYGgZtLjgHPgqFJtnXY9ennu9EUmI+10aLiUbctNUa4p7HSst6wonKFfjAhZcj jjQHnaJrJT7zQ== Date: Wed, 11 Jun 2025 10:40:10 -0600 From: Keith Busch To: Manivannan Sadhasivam Cc: Keith Busch , bhelgaas@google.com, linux-pci@vger.kernel.org, ilpo.jarvinen@linux.intel.com, lukas@wunner.de Subject: Re: [PATCHv2] pci: allow user specifiy a reset poll timeout Message-ID: References: <20250218165444.2406119-1-kbusch@meta.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 Wed, Jun 11, 2025 at 09:58:59PM +0530, Manivannan Sadhasivam wrote: > On Mon, Apr 14, 2025 at 06:11:44PM -0600, Keith Busch wrote: > > On Tue, Feb 18, 2025 at 08:54:44AM -0800, Keith Busch wrote: > > > From: Keith Busch > > > > > > The spec does not provide any upper limit to how long a device may > > > return Request Retry Status. It just says "Some devices require a > > > lengthy self-initialization sequence to complete". The kernel > > > arbitrarily chose 60 seconds since that really ought to be enough. But > > > there are devices where this turns out not to be enough. > > > > > > Since any timeout choice would be arbitrary, and 60 seconds is generally > > > more than enough for the majority of hardware, let's make this a > > > parameter so an admin can adjust it specifically to their needs if the > > > default timeout isn't appropriate. > > > > This patch is trying to address timings that have no spec defined > > behavior, so making it user tunable sounds just more reasonable than a > > kernel define. If we're not considering upstream options to make this > > tunable, I think we have no choice but to continue with bespoke > > out-of-tree solutions. > > Do we know the list of devices exhibiting this pattern? And does the time limit > is deterministic? I'm just trying to see if it is possible to add quirks for > those devices. No. I'm dealing with new devices being actively developed, with new ones coming out every year, so a quirk list would just be never ending maintenance pain point. The fact I can't point them to off-the-shelf kernels to test with has been frustrating for everyone. If we just had a user defined option instead of forcing the kernel's arbitrary choice, then the problem is solved once and forever.