From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lukas Wunner Subject: Re: [PATCH 10/11] acpi: Export acpi_bus_type Date: Tue, 19 Jan 2016 00:00:47 +0100 Message-ID: <20160118230047.GA9173@wunner.de> References: <1452752207-30382-1-git-send-email-ankitprasad.r.sharma@intel.com> <11845387.lHudWAleac@vostro.rjw.lan> <20160118223907.GA9156@wunner.de> <1530202.t7e2q1JhJ2@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Content-Disposition: inline In-Reply-To: <1530202.t7e2q1JhJ2@vostro.rjw.lan> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: "Rafael J. Wysocki" Cc: Ankitprasad Sharma , intel-gfx@lists.freedesktop.org, shashidhar.hiremath@intel.com, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, akash.goel@intel.com, Len Brown List-Id: linux-acpi@vger.kernel.org SGksCgpPbiBNb24sIEphbiAxOCwgMjAxNiBhdCAxMTo0NjoxOFBNICswMTAwLCBSYWZhZWwgSi4g V3lzb2NraSB3cm90ZToKPiBPbiBNb25kYXksIEphbnVhcnkgMTgsIDIwMTYgMTE6Mzk6MDcgUE0g THVrYXMgV3VubmVyIHdyb3RlOgo+ID4gSGksCj4gPiAKPiA+IE9uIE1vbiwgSmFuIDE4LCAyMDE2 IGF0IDExOjI4OjI3UE0gKzAxMDAsIFJhZmFlbCBKLiBXeXNvY2tpIHdyb3RlOgo+ID4gPiBPbiBN b25kYXksIEphbnVhcnkgMTgsIDIwMTYgMDM6NTc6MjkgUE0gUmFmYWVsIEouIFd5c29ja2kgd3Jv dGU6Cj4gPiA+ID4gT24gTW9uZGF5LCBKYW51YXJ5IDE4LCAyMDE2IDAyOjMxOjAwIFBNIEFua2l0 cHJhc2FkIFNoYXJtYSB3cm90ZToKPiA+ID4gPiA+IE9uIEZyaSwgMjAxNi0wMS0xNSBhdCAxNTo1 MSArMDEwMCwgUmFmYWVsIEouIFd5c29ja2kgd3JvdGU6Cj4gPiA+ID4gPiA+IE9uIFRodXJzZGF5 LCBKYW51YXJ5IDE0LCAyMDE2IDExOjQ2OjQ2IEFNIGFua2l0cHJhc2FkLnIuc2hhcm1hQGludGVs LmNvbSB3cm90ZToKPiA+ID4gPiA+ID4gPiBGcm9tOiBBbmtpdHByYXNhZCBTaGFybWEgPGFua2l0 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cy5mcmVlZGVza3RvcC5vcmcKaHR0cDovL2xpc3RzLmZyZWVkZXNrdG9wLm9yZy9tYWlsbWFuL2xp c3RpbmZvL2ludGVsLWdmeAo= From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932512AbcARXHU (ORCPT ); Mon, 18 Jan 2016 18:07:20 -0500 Received: from mailout1.hostsharing.net ([83.223.95.204]:44143 "EHLO mailout1.hostsharing.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932389AbcARXHR (ORCPT ); Mon, 18 Jan 2016 18:07:17 -0500 X-Greylist: delayed 384 seconds by postgrey-1.27 at vger.kernel.org; Mon, 18 Jan 2016 18:07:16 EST Date: Tue, 19 Jan 2016 00:00:47 +0100 From: Lukas Wunner To: "Rafael J. Wysocki" Cc: Ankitprasad Sharma , intel-gfx@lists.freedesktop.org, akash.goel@intel.com, shashidhar.hiremath@intel.com, tvrtko.ursulin@linux.intel.com, Len Brown , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 10/11] acpi: Export acpi_bus_type Message-ID: <20160118230047.GA9173@wunner.de> References: <1452752207-30382-1-git-send-email-ankitprasad.r.sharma@intel.com> <11845387.lHudWAleac@vostro.rjw.lan> <20160118223907.GA9156@wunner.de> <1530202.t7e2q1JhJ2@vostro.rjw.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1530202.t7e2q1JhJ2@vostro.rjw.lan> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Mon, Jan 18, 2016 at 11:46:18PM +0100, Rafael J. Wysocki wrote: > On Monday, January 18, 2016 11:39:07 PM Lukas Wunner wrote: > > Hi, > > > > On Mon, Jan 18, 2016 at 11:28:27PM +0100, Rafael J. Wysocki wrote: > > > On Monday, January 18, 2016 03:57:29 PM Rafael J. Wysocki wrote: > > > > On Monday, January 18, 2016 02:31:00 PM Ankitprasad Sharma wrote: > > > > > On Fri, 2016-01-15 at 15:51 +0100, Rafael J. Wysocki wrote: > > > > > > On Thursday, January 14, 2016 11:46:46 AM ankitprasad.r.sharma@intel.com wrote: > > > > > > > From: Ankitprasad Sharma > > > > > > > > > > > > > > Some modules, like i915.ko, needs to detect when certain ACPI features > > > > > > > are active inorder to prevent corruption on contended resources. > > > > > > > In particular, use of BIOS RapidStart Technology may corrupt the contents > > > > > > > of the reserved graphics memory, due to unalarmed hibernation. In which > > > > > > > case i915.ko cannot assume that it (reserved gfx memory) remains > > > > > > > unmodified and must recreate teh contents and importantly not use it to > > > > > > > store unrecoverable user data. > > > > > > > > > > > > > > Signed-off-by: Ankitprasad Sharma > > > > > > > Cc: "Rafael J. Wysocki" > > > > > > > Cc: Len Brown > > > > > > > Cc: linux-acpi@vger.kernel.org > > > > > > > Cc: linux-kernel@vger.kernel.org > > > > > > > --- > > > > > > > drivers/acpi/bus.c | 1 + > > > > > > > 1 file changed, 1 insertion(+) > > > > > > > > > > > > > > diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c > > > > > > > index a212cef..69509c7 100644 > > > > > > > --- a/drivers/acpi/bus.c > > > > > > > +++ b/drivers/acpi/bus.c > > > > > > > @@ -814,6 +814,7 @@ struct bus_type acpi_bus_type = { > > > > > > > .remove = acpi_device_remove, > > > > > > > .uevent = acpi_device_uevent, > > > > > > > }; > > > > > > > +EXPORT_SYMBOL_GPL(acpi_bus_type); > > > > > > > > > > > > > > /* -------------------------------------------------------------------------- > > > > > > > Initialization/Cleanup > > > > > > > > > > > > > > > > > > > No. > > > > > > > > > > > > I see no reason whatsoever for doing this. > > > > > > > > > > > > Thanks, > > > > > > Rafael > > > > > Hi Rafael, > > > > > > > > > > Thanks for the response. > > > > > > > > > > Can you please help me with, how to detect the presence of a certain > > > > > acpi device using its id (for example, INT3392 for Intel RST device)? > > > > > > > > If you want to check if the device ir present at all, you cen use > > > > acpi_device_is_present() introduced recently (although that would need > > > > to be exported if you want to use it from a driver). > > > > > > I meant acpi_dev_present(), sorry about the mistake. > > > > > > I guess we should rename it to acpi_device_found() or something similar > > > to avoid such confusion in the future. > > > > The name was chosen because the PCI equivalent is called pci_dev_present() > > and I assumed that name already stuck in developers' heads, so if they're > > looking for an ACPI presence detection function, that's what they'd look > > for first. > > But "present" in ACPI really means something different. There may be ACPI > device objects in the namespace for devices that are not *actually* present. You mean synthesized devices like LNXSYBUS? Don't think anyone is going to test for the presence of that. I've posted 5 patches over the last days which use acpi_dev_present(): http://lists.freedesktop.org/archives/dri-devel/2016-January/098403.html http://mailman.alsa-project.org/pipermail/alsa-devel/2016-January/103056.html http://mailman.alsa-project.org/pipermail/alsa-devel/2016-January/103058.html http://thread.gmane.org/gmane.linux.drivers.platform.x86.devel/8474/focus=8475 http://thread.gmane.org/gmane.linux.drivers.platform.x86.devel/8474/focus=8476 When considering a rename of the function, please bear in mind that it will cause breakage for anyone testing or merging these patches. (Postponing a rename until these patches have landed would avoid that.) Thanks, Lukas