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 36B05C3A5A2 for ; Thu, 22 Aug 2019 21:10:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D533A233FC for ; Thu, 22 Aug 2019 21:10:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566508230; bh=8lmA4y+c41NSfIWmIwk3izt7RyEIzi1EgDtTezS9EJU=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=IW4OAR+10g9Dnya0o0Anx32T1Gza8QXftMdzdl8KNk50yTIpqLNTCe7g5JoYbgG42 4IR9DBXx8lJoGi9FrNcz4KKtvb3AGfuCarDiPycJ8oEyjqbbYFlr2DL0a9F8ceIZ8c 6IGqI4oLgot0twFvqYk55pn+ukefJG6mc4Vx3UEg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731184AbfHVVKa (ORCPT ); Thu, 22 Aug 2019 17:10:30 -0400 Received: from mail-oi1-f195.google.com ([209.85.167.195]:41139 "EHLO mail-oi1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730991AbfHVVKa (ORCPT ); Thu, 22 Aug 2019 17:10:30 -0400 Received: by mail-oi1-f195.google.com with SMTP id g7so5463557oia.8; Thu, 22 Aug 2019 14:10:29 -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=722k5ddNheSppDzrG90q8EFQ8uGNK424zDmyHBRv/xk=; b=sQ2/Kgp64yj3UAzuBYxwngzdEsHH68xa0fs511sEE7FtajN+DcF1jQOnBWTeCAwwop pGu30/wuYeVTLFG5Fy/hP3qmpKk/s/cL28i5K2pxyFhNOCHMFSUhv6v4JomnSyG87xE1 J0VY5ivLVW5m5dIn5Tyy5HSF85sLplKjOokZM0KygO5aR+qV1eEX4SAyLVXR/4cPVfBk d/Sftdg/wypUFxiCcFUAot2RcoAhuGC96MxT1COkz0WT7F52AUEZUKcQA79xPHXI2Dn9 CVijj2x673H//O8eNn0wuPu0IuWBmWiS0XNmePGTHnl2rZLPozQANXUREqck2Eio086G eE2Q== X-Gm-Message-State: APjAAAVxoKcx6P0vbNKiGYizjfPYfTh3eRMFJMchzbeQvR+Hhi1S5FUE /FujHt6ThG5kcPV9GYrhUerSjSeUuXjmO/+kmoA= X-Google-Smtp-Source: APXvYqzipBbFAy30yqllDRxVg2wDXWGv50k8XyQth34p3InV0dg8l5sHIhCCRt/28NsM9VDdy0aBudPzL12G7mXE8DE= X-Received: by 2002:aca:4dd8:: with SMTP id a207mr756501oib.115.1566508228550; Thu, 22 Aug 2019 14:10:28 -0700 (PDT) MIME-Version: 1.0 References: <20190822200551.129039-1-helgaas@kernel.org> <20190822200551.129039-4-helgaas@kernel.org> In-Reply-To: <20190822200551.129039-4-helgaas@kernel.org> From: "Rafael J. Wysocki" Date: Thu, 22 Aug 2019 23:10:17 +0200 Message-ID: Subject: Re: [PATCH 3/3] 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-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Thu, Aug 22, 2019 at 10:06 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 | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index 5f0a3145c3f2..41112af189a8 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -853,6 +853,12 @@ 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, "can't access config space to change power state from %s to %s\n", > + pci_power_name(dev->current_state), > + pci_power_name(state)); > + return -EIO; > + } > > /* > * If we're (effectively) in D3, force entire word to 0. > @@ -893,8 +899,9 @@ static int pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state) > pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr); > dev->current_state = (pmcsr & PCI_PM_CTRL_STATE_MASK); > if (dev->current_state != state && printk_ratelimit()) > - pci_info(dev, "refused to change power state (currently %s)\n", > - pci_power_name(dev->current_state)); > + pci_info(dev, "refused to change power state from %s to %s\n", > + pci_power_name(dev->current_state), > + pci_power_name(state)); > > /* > * According to section 5.4.1 of the "PCI BUS POWER MANAGEMENT > -- > 2.23.0.187.g17f5b7556c-goog >