Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758063Ab0FOPMI (ORCPT ); Tue, 15 Jun 2010 11:12:08 -0400 Received: from mx1.redhat.com ([209.132.183.28]:4851 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755297Ab0FOPME (ORCPT ); Tue, 15 Jun 2010 11:12:04 -0400 Message-ID: <4C17983F.8020405@redhat.com> Date: Tue, 15 Jun 2010 17:11:59 +0200 From: Tomas Henzl User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100430 Fedora/3.0.4-2.fc12 Thunderbird/3.0.4 MIME-Version: 1.0 To: Matthew Garrett CC: linux-pci@vger.kernel.org, jbarnes@virtuousgeek.org, linux-kernel@vger.kernel.org, kaneshige.kenji@jp.fujitsu.com Subject: Re: [PATCH] pci: Don't enable aspm before drivers have had a chance to veto it References: <1276113907-22432-1-git-send-email-mjg@redhat.com> In-Reply-To: <1276113907-22432-1-git-send-email-mjg@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2246 Lines: 60 On 06/09/2010 10:05 PM, Matthew Garrett wrote: > The aspm code will currently set the configured aspm policy before drivers > have had an opportunity to indicate that their hardware doesn't support it. > Unfortunately, putting some hardware in L0 or L1 can result in the hardware > no longer responding to any requests, even after aspm is disabled. It makes > more sense to leave aspm policy at the BIOS defaults at initial setup time, > reconfiguring it after pci_enable_device() is called. This allows the > driver to blacklist individual devices beforehand. > > Signed-off-by: Matthew Garrett > --- > > Cleaned up slightly to remove the hacky aspm_policy changing. > > drivers/pci/pcie/aspm.c | 16 ++++++++++++++-- > 1 files changed, 14 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c > index be53d98..7122281 100644 > --- a/drivers/pci/pcie/aspm.c > +++ b/drivers/pci/pcie/aspm.c > @@ -588,11 +588,23 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev) > * update through pcie_aspm_cap_init(). > */ > pcie_aspm_cap_init(link, blacklist); > - pcie_config_aspm_path(link); > > /* Setup initial Clock PM state */ > pcie_clkpm_cap_init(link, blacklist); > - pcie_set_clkpm(link, policy_to_clkpm_state(link)); > + > + /* > + * At this stage drivers haven't had an opportunity to change the > + * link policy setting. Enabling ASPM on broken hardware can cripple > + * it even before the driver has had a chance to disable ASPM, so > + * default to a safe level right now. If we're enabling ASPM beyond > + * the BIOS's expectation, we'll do so once pci_enable_device() is > + * called. > + */ > + if (aspm_policy != POLICY_POWERSAVE) { > + pcie_config_aspm_path(link); > + pcie_set_clkpm(link, policy_to_clkpm_state(link)); > + } > Matthew, isn't it so that the POLICY_DEFAULT will pass the above test and possibly switch the ASPM on? tomas > + > unlock: > mutex_unlock(&aspm_lock); > out: > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/