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 85274274670; Tue, 15 Jul 2025 12:31:10 +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=1752582670; cv=none; b=MkIrlABGU+snZHanwZcQljpsnpyBNOeGohCyM/sPzG/i9Gpc212VQ6btg6q9IqSjrgSp6QK8jWrfxTVnDpWfaVg3cZEOSyFoUJYtshPXzJIpFRHDzY52LIsVNGFLmXPkMy1SG+SPbdC0h7vggUtcPmpFlCethNGT8P5Vg9eE6ic= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752582670; c=relaxed/simple; bh=T1kRkbMbFy0pFWhOLhwbNykdfC7wFmv/WTrdLgvck6M=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=sJp62oIsYqgT5NhwBakhbnpykfHNixuLSgjpUAql8gxWdBQM3YLmAr8UdPTZGA/Dnbg+E0cXhNOo3nWSqpjuArGhQsUUJwkLFKSFZEaI+7w3ysI82z0K8g3/8VHEukWxJAqhQcGI6GHtNlaXEcQogBknbvazxYBSWnklF/fCVnc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eYCsxBJn; 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="eYCsxBJn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67478C4CEE3; Tue, 15 Jul 2025 12:31:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1752582670; bh=T1kRkbMbFy0pFWhOLhwbNykdfC7wFmv/WTrdLgvck6M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=eYCsxBJnRHRyFfKAR8IQhOrM0qHfEma/BetdIk8M7+tTmfgLrdxy9lT9q7832Ntxb v2sJeaIHduxsNo6IzD/wYzP+hKnmvoYbGYXpywOQuvsLxH393WIQBB8k3jlqwzgiXh DnQhXpneYjrYLyqs5cQUumvShn01SFjp3PDJMPNnLhGGluh00oBIqpLkOwem65yARi QXfCB0RYPr3AyolFWWY8v9W9Rttp0FKbfB4m8KEXT5cLm8drqUeF2nMCtQE5XBtTdH r2Lia5gLtLfOLk+n/bf+ofjkw39hmqEGRiuDrtExVszp6TLtXdE13iDDunu4B6Ay3U jIslcbRKdC56g== Received: from johan by xi.lan with local (Exim 4.97.1) (envelope-from ) id 1ubeoL-000000008Eb-3LCP; Tue, 15 Jul 2025 14:31:06 +0200 Date: Tue, 15 Jul 2025 14:31:05 +0200 From: Johan Hovold To: Manivannan Sadhasivam Cc: Manivannan Sadhasivam , Lorenzo Pieralisi , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Rob Herring , Bjorn Helgaas , linux-arm-msm@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Krishna Chaitanya Chundru , stable@vger.kernel.org Subject: Re: [PATCH 1/2] PCI: qcom: Switch to bus notifier for enabling ASPM of PCI devices Message-ID: References: <20250714-aspm_fix-v1-0-7d04b8c140c8@oss.qualcomm.com> <20250714-aspm_fix-v1-1-7d04b8c140c8@oss.qualcomm.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 Tue, Jul 15, 2025 at 03:57:12PM +0530, Manivannan Sadhasivam wrote: > On Tue, Jul 15, 2025 at 11:33:16AM GMT, Johan Hovold wrote: > > On Tue, Jul 15, 2025 at 02:41:23PM +0530, Manivannan Sadhasivam wrote: > > > On Tue, Jul 15, 2025 at 09:48:30AM GMT, Johan Hovold wrote: > > > > A problem with this approach is that ASPM will never be enabled (and > > > > power consumption will be higher) in case an endpoint driver is missing. > > > > > > I'm aware of this limiation. But I don't think we should really worry about that > > > scenario. No one is going to run an OS intentionally with a PCI device and > > > without the relevant driver. If that happens, it might be due to some issue in > > > driver loading or the user is doing it intentionally. Such scenarios are short > > > lived IMO. > > > > There may not even be a driver (yet). A user could plug in whatever > > device in a free slot. I can also imagine someone wanting to blacklist > > a driver temporarily for whatever reason. > > Yes, that's why I said these scenarios are 'shortlived'. My point is the opposite; that you should not make such assumptions (e.g. hardware not supported by linux or drivers disabled due to stability or security concerns). Johan