From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by ozlabs.org (Postfix) with ESMTP id DAA472C0089 for ; Mon, 4 Feb 2013 14:22:57 +1100 (EST) Date: Sun, 3 Feb 2013 19:24:47 -0600 From: Greg KH To: "Rafael J. Wysocki" Subject: Re: [PATCH?] Move ACPI device nodes under /sys/firmware/acpi (was: Re: [RFC PATCH v2 01/12] Add sys_hotplug.h for system device hotplug framework) Message-ID: <20130204012447.GB6433@kroah.com> References: <1357861230-29549-1-git-send-email-toshi.kani@hp.com> <20130202145801.GB1434@kroah.com> <1810611.i6Sc4oLaux@vostro.rjw.lan> <2806030.VWUMy6F7lm@vostro.rjw.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <2806030.VWUMy6F7lm@vostro.rjw.lan> Cc: linux-s390@vger.kernel.org, Toshi Kani , jiang.liu@huawei.com, wency@cn.fujitsu.com, linux-acpi@vger.kernel.org, yinghai@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, isimatu.yasuaki@jp.fujitsu.com, srivatsa.bhat@linux.vnet.ibm.com, guohanjun@huawei.com, bhelgaas@google.com, akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org, lenb@kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sat, Feb 02, 2013 at 11:18:20PM +0100, Rafael J. Wysocki wrote: > On Saturday, February 02, 2013 09:15:37 PM Rafael J. Wysocki wrote: > > On Saturday, February 02, 2013 03:58:01 PM Greg KH wrote: > [...] > > > > > I know it's more complicated with these types of devices, and I think we > > > are getting closer to the correct solution, I just don't want to ever > > > see duplicate devices in the driver model for the same physical device. > > > > Do you mean two things based on struct device for the same hardware component? > > That's been happening already pretty much forever for every PCI device known > > to the ACPI layer, for PNP and many others. However, those ACPI things are (or > > rather should be, but we're going to clean that up) only for convenience (to be > > able to see the namespace structure and related things in sysfs). So the stuff > > under /sys/devices/LNXSYSTM\:00/ is not "real". In my view it shouldn't even > > be under /sys/devices/ (/sys/firmware/acpi/ seems to be a better place for it), > > but that may be difficult to change without breaking user space (maybe we can > > just symlink it from /sys/devices/ or something). And the ACPI bus type > > shouldn't even exist in my opinion. > > Well, well. > > In fact, the appended patch moves the whole ACPI device nodes tree under > /sys/firmware/acpi/ and I'm not seeing any negative consequences of that on my > test box (events work and so on). User space is quite new on it, though, and > the patch is hackish. Try booting a RHEL 5 image on this type of kernel, or some old Fedora releases, they were sensitive to changes in sysfs. greg k-h