From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x225ZwNycZrgtRR0eA0YXc9PSzKFQHu98RP+gQ6kVlK0cL6nD0SrbwxZbdkEZkIyw+IhoMiux ARC-Seal: i=1; a=rsa-sha256; t=1519082912; cv=none; d=google.com; s=arc-20160816; b=S4TGyvSCc85nGAJd2NQRVfvBjblzMIIlRvR424N8NFbCzGfejTl/7560Lhd0KqnVYB hA6FRHRveC6PFBOZisqFjQzEHky2S0lTVnJwo+KWlm6duiuPmIL5YG2dGtUZF034/IRY ZhtwqGQ4LCw65w/IkJURFlsp0YrjELXW2y3TsXprDu4ZrAfZkfxn6RLSEc0quxWyHyGa rt08hUyv7MhT8piqMOxoO7baBJKfcaHYrXY3Pjg0wnCD69gS7G2I1uGne5tXtImI3g3P UlJrsLzovwgAi/5VJoe4TrSnRfcIM4VPidkAM+TdPNMSXtKj5MTOn2Z1Jp1y6jvP4Jf4 IAHA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=message-id:date:content-transfer-encoding:mime-version:references :in-reply-to:subject:cc:to:from:sender:arc-authentication-results; bh=B1zSPhnk5R9JgqrgdjfouPmooFz2RU/U7PMH4s2puKs=; b=TzT0s+mTph7EiySm+6JaPb76BGuSS2D3vg/PD3fNNQ+nre6W8q/3vY2GSG5f5EanV3 uIy8gkUOFrpe4yFORvHaeT2XtVK52m2scwrVxtiR/ft0jQLLBqpMIZ466w9DdslS70IJ mFOJ4s34NlkagQ+CBa0KtrEfWO1NSDcZeg3P5OrkBh3d0PEuuEgd0vPVU6HAA9b6zRyx 00DOpREclPQ3+xno3c3BPkMLB0vVybfTsr77UkyVoMH1xqb7zmhrILRFdqACS88i+M4w rc97FzkBOQ/OXSoXeFzOlgk1onji402i04+25OjRjUPu8Mb4N6UPiBdbvHfHmWFiZ/xb TSTQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of valdis@vt.edu designates 2607:b400:92:8300:0:c6:2117:b0e as permitted sender) smtp.mailfrom=valdis@vt.edu; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=vt.edu Authentication-Results: mx.google.com; spf=pass (google.com: domain of valdis@vt.edu designates 2607:b400:92:8300:0:c6:2117:b0e as permitted sender) smtp.mailfrom=valdis@vt.edu; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=vt.edu Sender: Valdis Kletnieks From: valdis.kletnieks@vt.edu X-Google-Original-From: Valdis.Kletnieks@vt.edu X-Mailer: exmh version 2.8.0 04/21/2017 with nmh-1.7+dev To: Bjorn Helgaas Cc: linux-pci@vger.kernel.org, Mathias Nyman , linux-pm@vger.kernel.org, Mika Westerberg , "Rafael J. Wysocki" , linux-kernel@vger.kernel.org, Lukas Wunner , Peter Wu , Qipeng Zha , Greg Kroah-Hartman , Andreas Noever , Dave Airlie , Qi Zheng Subject: Re: [PATCH v1 2/2] PCI: Allow user to request power management of conventional and hotplug bridges In-Reply-To: <151908204614.37696.12828004282495415825.stgit@bhelgaas-glaptop.roam.corp.google.com> References: <151908155159.37696.9710083237704994886.stgit@bhelgaas-glaptop.roam.corp.google.com> <151908204614.37696.12828004282495415825.stgit@bhelgaas-glaptop.roam.corp.google.com> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_1519082904_3347P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Date: Mon, 19 Feb 2018 18:28:24 -0500 Message-ID: <7778.1519082904@turing-police.cc.vt.edu> X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1592872976935903628?= X-GMAIL-MSGID: =?utf-8?q?1592873884741000472?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: --==_Exmh_1519082904_3347P Content-Type: text/plain; charset=us-ascii On Mon, 19 Feb 2018 17:14:06 -0600, Bjorn Helgaas said: > Change "pcie_port_pm=force" to enable power management of conventional PCI > bridges and hotplug bridges as well as PCIe ports. As with the previous > PCIe port-only behavior, this is not expected to work in all systems. This part says the behavior changes - which is itself a Bad Idea unless you have a deprecation cut-over across several releases. The general rule is that you're not allowed to break somebody's kernel without a lot of warning. Remember that there's probably a lot of embedded systems that hardcode their boot cmdline and changing the behavior can result in a failed boot - which can be a royal bitch to debug if the embedded system doesn't have a console..... In addition, it doesn't match the actual patch, which documents the boot parameter as being removed, rather than the behavior changed: > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 1d1d53f85ddd..4660105ec851 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -3143,10 +3147,6 @@ > compat Treat PCIe ports as PCI-to-PCI bridges, disable the PCIe > ports driver. > > - pcie_port_pm= [PCIE] PCIe port power management handling: > - off Disable power management of all PCIe ports > - force Forcibly enable power management of all PCIe ports > - And *that* doesn't match the rest of the patch, which never touches the handling of that parameter, either changing it or removing it. --==_Exmh_1519082904_3347P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Comment: Exmh version 2.8.0 04/21/2017 iQEVAwUBWotdmI0DS38y7CIcAQIFNgf/Voo1PhvVYqriKAKxYoK9fDPbW7e5I/CQ RyGJmtTIvp+AZNCcZUv1OMQYitmPzUPDSDcYcwaDDRS/y06kV78U+lE+rpr1OuPA k6DLH7LX3vM30nHY6Pt2uxeDWK7otdCByBZwrrFMo0IqJle/2sK/RcFfkr3B1+24 wo8QO3Gnq/u44KMaGaEUz3plZN2z0ZcKPf3Wffy6CTPSzwy38K55tbjqhylhpYJL HQ5LYC6WP2LsAAQ8jJ3VeZGY9OoVZcz2c1JH9PxdIrFr3R5zcYmEQhGBPmya3yF9 J/jqc10cp0fx9YiexZxU+UdaaZpK3Yf5/rdoX7AWB2ZdhqnTEFpBIw== =TDtU -----END PGP SIGNATURE----- --==_Exmh_1519082904_3347P--