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 6383C1DED4F; Mon, 28 Oct 2024 16:12:59 +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=1730131979; cv=none; b=ABjNfRRe6WpvwB3rd7Yz/ffbaDXqU/vADN13n7D3yDuV/F+qRfziFGurIP2aU9B0MkG2/ZCc/rOOqtywEArJdOkhiiubu7XtyJkHHeh9c5Z0JQqtOLI4O7pAe76cM740nFONaLHeKOjuZ5VHUBSjYCWLezv13zIlRGf5+/LN05o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730131979; c=relaxed/simple; bh=xuzSVIC+24hcvUH3Uu6IJyxDoI8NF9z/u0YhE9kqbOY=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=JNVP7hAqgExtXzxI3tlfkFXEQ2r0Oh9VSkcLoHN6QV+2RQCU6kL3CW+ZAP/NxVW14yT9xT0dmL9dKEgVRLYLbS8DHPjoPv+Z+Tpjruwq9rEhOBkjiE0niCqhpShKnshaYzgFDRP+drXMRIipma+Z8ZaiegD/BQozJXkLFlMxVrA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=C0q+lkSK; 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="C0q+lkSK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AC1B6C4CEC3; Mon, 28 Oct 2024 16:12:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730131979; bh=xuzSVIC+24hcvUH3Uu6IJyxDoI8NF9z/u0YhE9kqbOY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=C0q+lkSKR1cXdmfA70QriKxNHoGAVcH+ZKCc+Zox4ygDHb48qTdn8VuHT2A4+o5V2 zoili6j4ZeZdYddsbvCBmzv4/WQgpSj7kTlw06ahaK4hCP3zTRP9o3R85+DvpU2GYF JOfOD4cd4nqkmkIlo1feNr7WS5I7Lq9w9Ag0huIfm0H86flbsmELoeR1CWqpKwnAA6 NYQH1pJbxeuWuW0ou07d6MW7v+ovxkDt0VgRA/OeSEyVzpisDjPRrKkn0IRURMLEiE huG9vkW7i5jsybC0co+F32KJLuGZov4R0mWfhQFuXfe18nE4zlmADox5tRHMwhBpHw r+wobvKfES9+g== Date: Mon, 28 Oct 2024 09:12:56 -0700 From: Jakub Kicinski To: David Woodhouse Cc: Richard Cochran , Peter Hilber , linux-kernel@vger.kernel.org, virtualization@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-rtc@vger.kernel.org, "Ridoux, Julien" , virtio-dev@lists.linux.dev, "Luu, Ryan" , "Chashper, David" , "Mohamed Abuelfotoh, Hazem" , Paolo Abeni , "Christopher S . Hall" , Jason Wang , John Stultz , "Michael S . Tsirkin" , netdev@vger.kernel.org, Stephen Boyd , Thomas Gleixner , Xuan Zhuo , Marc Zyngier , Mark Rutland , Daniel Lezcano , Alessandro Zummo , Alexandre Belloni , qemu-devel , Simon Horman Subject: Re: [PATCH net-next v7] ptp: Add support for the AMZNC10C 'vmclock' device Message-ID: <20241028091256.1b0752b4@kernel.org> In-Reply-To: References: <78969a39b51ec00e85551b752767be65f6794b46.camel@infradead.org> <20241009173253.5eb545db@kernel.org> <20241014131238.405c1e58@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Sat, 19 Oct 2024 18:49:24 +0100 David Woodhouse wrote: > > Yes please and thank you! We gotta straighten it out before > > the merge window. > > Hm, as I (finally) come to do that, I realise that many of the others > defined in drivers/ptp/Kconfig are also 'default y'. Which is only > really 'default PTP_1588_CLOCK' in practice since they all depend on > that. AFAICT nothing defaulted to enabled since 2017, so I'd chalk it up to us getting better at catching mistakes over time. > Most importantly, PTP_1588_CLOCK_KVM is 'default y'. And that one is > fundamentally broken (at least in the presence of live migration if > guests care about their clock suddenly being wrong) which is why it's > being superseded by the new VMCLOCK thing. We absolutely don't want to > leave the _KVM one enabled by default and not its _VMCLOCK replacement. You can default to .._CLOCK_KVM, and provide the explanation in the commit message and Kconfig help. Or if you feel strongly even make CLOCK_KVM depend on the new one? > Please advise... I suspect the best answer is to leave it as it is? I'd really rather not. Linus has complained to us about Kconfig symbols appearing / getting enabled by default multiple times in the past. Sorry for the delay, vacation time.