From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Kroah-Hartman Subject: Re: [RFC PATCH v5 7/8] PCI/PCIe: add "pci=nopciehp" to disable PCIe native hotplug Date: Sat, 19 Jan 2013 06:51:47 -0800 Message-ID: <20130119145147.GB2491@kroah.com> References: <1358525267-14268-1-git-send-email-jiang.liu@huawei.com> <1358525267-14268-8-git-send-email-jiang.liu@huawei.com> <50F9FD48.20509@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail.kernel.org ([198.145.19.201]:39558 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751120Ab3ASOuf (ORCPT ); Sat, 19 Jan 2013 09:50:35 -0500 Content-Disposition: inline In-Reply-To: <50F9FD48.20509@gmail.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Yijing Wang Cc: Bjorn Helgaas , Jiang Liu , "Rafael J . Wysocki" , Jiang Liu , Yinghai Lu , Kenji Kaneshige , Yijing Wang , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, ACPI Devel Maling List , Toshi Kani , Myron Stowe On Sat, Jan 19, 2013 at 09:56:24AM +0800, Yijing Wang wrote: > =E4=BA=8E 2013-01-19 1:35, Bjorn Helgaas =E5=86=99=E9=81=93: > > On Fri, Jan 18, 2013 at 9:07 AM, Jiang Liu wrote= : > >> If user specifies "pci=3Dnopciehp" on kernel boot command line, OS= PM > >> won't claim PCIe native hotplug service from firmware and no PCIe > >> port devices will be created for PCIe native hotplug service. > >=20 > > Why do we need this option? > >=20 > > If I understand correctly, there are machines where it *looks* like= we > > should use pciehp, but pciehp doesn't work because we don't get the > > interrupts we expect. On those machines, we have to use acpiphp > > instead. It seems like many Dell XPS laptops have this issue with > > ExpressCard slots, e.g., > > https://bugzilla.kernel.org/show_bug.cgi?id=3D40802 . >=20 > What about use modprobe pciehp pciehp_poll_mode=3D1? > If just cannot receive the interrupt, maybe this module parameter wil= l fix it. You can't add a new option that you now force hardware that was working with a different module to now define and use. It needs to be "automatic". > > If you want "pci=3Dnopciehp" as a way for users to deal with this > > problem by forcing the use of acpiphp, I object. Windows manages t= o > > make these slots work without having users do anything special, so = we > > should be able to do it, too. >=20 > In fact, pcie native hotplug may not be implemented perfectly, Oh, we know that is true, it's the problem here. Fixing BIOSes would b= e nice, but we can't do that :( greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Sat, 19 Jan 2013 06:51:47 -0800 From: Greg Kroah-Hartman To: Yijing Wang Cc: Bjorn Helgaas , Jiang Liu , "Rafael J . Wysocki" , Jiang Liu , Yinghai Lu , Kenji Kaneshige , Yijing Wang , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, ACPI Devel Maling List , Toshi Kani , Myron Stowe Subject: Re: [RFC PATCH v5 7/8] PCI/PCIe: add "pci=nopciehp" to disable PCIe native hotplug Message-ID: <20130119145147.GB2491@kroah.com> References: <1358525267-14268-1-git-send-email-jiang.liu@huawei.com> <1358525267-14268-8-git-send-email-jiang.liu@huawei.com> <50F9FD48.20509@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 In-Reply-To: <50F9FD48.20509@gmail.com> Sender: linux-acpi-owner@vger.kernel.org List-ID: On Sat, Jan 19, 2013 at 09:56:24AM +0800, Yijing Wang wrote: > 于 2013-01-19 1:35, Bjorn Helgaas 写道: > > On Fri, Jan 18, 2013 at 9:07 AM, Jiang Liu wrote: > >> If user specifies "pci=nopciehp" on kernel boot command line, OSPM > >> won't claim PCIe native hotplug service from firmware and no PCIe > >> port devices will be created for PCIe native hotplug service. > > > > Why do we need this option? > > > > If I understand correctly, there are machines where it *looks* like we > > should use pciehp, but pciehp doesn't work because we don't get the > > interrupts we expect. On those machines, we have to use acpiphp > > instead. It seems like many Dell XPS laptops have this issue with > > ExpressCard slots, e.g., > > https://bugzilla.kernel.org/show_bug.cgi?id=40802 . > > What about use modprobe pciehp pciehp_poll_mode=1? > If just cannot receive the interrupt, maybe this module parameter will fix it. You can't add a new option that you now force hardware that was working with a different module to now define and use. It needs to be "automatic". > > If you want "pci=nopciehp" as a way for users to deal with this > > problem by forcing the use of acpiphp, I object. Windows manages to > > make these slots work without having users do anything special, so we > > should be able to do it, too. > > In fact, pcie native hotplug may not be implemented perfectly, Oh, we know that is true, it's the problem here. Fixing BIOSes would be nice, but we can't do that :( greg k-h