From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9BB03C433FF for ; Mon, 5 Aug 2019 21:15:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6F57A2186A for ; Mon, 5 Aug 2019 21:15:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565039727; bh=SFmb97/nqbGwMChG+UQFQCxD8PDL73XUMKRmUhfbqcU=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=tWFS6pcGF7Oru1ME24IL8hn7d/LE0JzrlJsMcsdVUUm7D7BRtVkHYCFXOTgyCRoJQ jXjOaabL+S6fqUb2eDXQ3fFoM+GjLYj/1lERe80xmNYOdCZziy7OAuZ+3ow0WlAk/X tnFP8Zeu8o17SA7OBsHbC435aQkpZHpYHZZGA2ZM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730801AbfHEVP0 (ORCPT ); Mon, 5 Aug 2019 17:15:26 -0400 Received: from mail-oi1-f194.google.com ([209.85.167.194]:42587 "EHLO mail-oi1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729383AbfHEVP0 (ORCPT ); Mon, 5 Aug 2019 17:15:26 -0400 Received: by mail-oi1-f194.google.com with SMTP id s184so63418287oie.9; Mon, 05 Aug 2019 14:15:26 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=fX0uLeu4WyBXdgrz/XI2vSyMGlamTcEZJr5vMDYwpvE=; b=DK2t3PvZajPjOjcnnm8uK3XCVYmZK4RMkaqj03optfVNfkSOsjD6RfG6/4AEcArdab FMuFsYjj1lcmFpsym9CU/z3CnrHpj3kbrGX7a0WHNUz3SVuNeC34V+l7o2AxH4baKmdH YHl6fEhjbM6rQZ/0mucVSHVnFfTKoO945AqsXqSs0MjBzqVOP53K+3Mzb07WmLJa38P1 2ZduJWfdJGNAqI1Kw7v8Tsmajo5G9JC6YtcHKG/YLYdc3SNIDZK5pJLbxI8M2DlSuWtI X2yYQ2nOB2UCBMkxZSreLih2niZFnNbKypHQRU1bj+hAQIL2xnQkXgt9gH6tRhVQdv81 WRNQ== X-Gm-Message-State: APjAAAWeRe+9BFSGEUB4rgBvMQcduThFgLGPF+SLgjWGgUp4QEzbOLTn /i5WYUxwmpd6FJHZLhvRsBxa8PH3fpgSa3cGEck= X-Google-Smtp-Source: APXvYqzxQdPHKAU8EvAofP903jPi7ejUZMMYbWg4JQHntbAQayhsorKwS0WljKzlHdSuvsZpv28j28exZINzhQdVTXw= X-Received: by 2002:aca:5a41:: with SMTP id o62mr280998oib.110.1565039725652; Mon, 05 Aug 2019 14:15:25 -0700 (PDT) MIME-Version: 1.0 References: <20190805205214.194981-1-helgaas@kernel.org> <20190805205214.194981-3-helgaas@kernel.org> In-Reply-To: <20190805205214.194981-3-helgaas@kernel.org> From: "Rafael J. Wysocki" Date: Mon, 5 Aug 2019 23:15:13 +0200 Message-ID: Subject: Re: [PATCH 2/5] PCI / PM: Return error when changing power state from D3cold To: Bjorn Helgaas Cc: Linux PCI , Lorenzo Pieralisi , Keith Busch , Greg Kroah-Hartman , "Rafael J . Wysocki" , Mika Westerberg , Linux PM , Linux Kernel Mailing List , Bjorn Helgaas Content-Type: text/plain; charset="UTF-8" Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Mon, Aug 5, 2019 at 10:52 PM Bjorn Helgaas wrote: > > From: Bjorn Helgaas > > pci_raw_set_power_state() uses the Power Management capability to change a > device's power state. The capability is in config space, which is > accessible in D0, D1, D2, and D3hot, but not in D3cold. > > If we call pci_raw_set_power_state() on a device that's in D3cold, config > reads fail and return ~0 data, which we erroneously interpreted as "the > device is in D3hot", leading to messages like this: > > pcieport 0000:03:00.0: Refused to change power state, currently in D3 > > The PCI_PM_CTRL has several RsvdP fields, so ~0 is never a valid register > value. Notice if we get that data, print a more informative message, and > return an error. > > Changing the power state of a device from D3cold must be done by a platform > power management method or some other non-config space mechanism. > > Signed-off-by: Bjorn Helgaas Reviewed-by: Rafael J. Wysocki > --- > drivers/pci/pci.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index bfc739dc6ada..984171d40858 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -851,6 +851,11 @@ static int pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state) > return -EIO; > > pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr); > + if (pmcsr == (u16) PCI_ERROR_RESPONSE) { > + pci_err(dev, "device not responding; can't change to power state D%d\n", > + state); > + return -EIO; > + } > > /* > * If we're (effectively) in D3, force entire word to 0. > -- > 2.22.0.770.g0f2c4a37fd-goog >