From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755843AbdDLVWt (ORCPT ); Wed, 12 Apr 2017 17:22:49 -0400 Received: from bh-25.webhostbox.net ([208.91.199.152]:42752 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755400AbdDLVWq (ORCPT ); Wed, 12 Apr 2017 17:22:46 -0400 Date: Wed, 12 Apr 2017 14:22:41 -0700 From: Guenter Roeck To: "Moore, Robert" Cc: "Zheng, Lv" , "Wysocki, Rafael J" , Len Brown , "linux-acpi@vger.kernel.org" , "devel@acpica.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] ACPICA: Export mutex functions Message-ID: <20170412212241.GA12384@roeck-us.net> References: <1492009990-3539-1-git-send-email-linux@roeck-us.net> <94F2FBAB4432B54E8AACC7DFDE6C92E37E5924DB@ORSMSX110.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <94F2FBAB4432B54E8AACC7DFDE6C92E37E5924DB@ORSMSX110.amr.corp.intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Authenticated_sender: guenter@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: guenter@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: guenter@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 12, 2017 at 03:29:55PM +0000, Moore, Robert wrote: > The ACPICA mutex functions are based on the host OS functions, so they don't really buy you anything. You should just use the native Linux functions. > You mean they don't really acquire the requested ACPI mutex, and the underlying DSDT which declares and uses the mutex just ignores if the mutex was acquired by acpi_acquire_mutex() ? To clarify: You are saying that code such as acpi_status status; status = acpi_acquire_mutex(NULL, "\\_SB.PCI0.SBRG.SIO1.MUT0", 0x10); if (ACPI_FAILURE(status)) { pr_err("Failed to acquire ACPI mutex\n"); return -EBUSY; } ... when used in conjunction with ... Mutex (MUT0, 0x00) Method (ENFG, 1, NotSerialized) { Acquire (MUT0, 0x0FFF) ... } doesn't really provide exclusive access to the resource(s) protected by MUT0, even if acpi_acquire_mutex() returns ACPI_SUCCESS ? Outch. Really ? Thanks, Guenter > > > -----Original Message----- > > From: Guenter Roeck [mailto:linux@roeck-us.net] > > Sent: Wednesday, April 12, 2017 8:13 AM > > To: Moore, Robert ; Zheng, Lv > > ; Wysocki, Rafael J ; > > Len Brown > > Cc: linux-acpi@vger.kernel.org; devel@acpica.org; linux- > > kernel@vger.kernel.org; Guenter Roeck > > Subject: [PATCH] ACPICA: Export mutex functions > > > > Mutex functions may be needed by drivers. Examples are accesses to > > Super-IO SIO registers (0x2e/0x2f or 0x4e/0x4f) or Super-IO > > environmental monitor registers, both which may also be accessed through > > DSDT. > > > > Signed-off-by: Guenter Roeck > > --- > > drivers/acpi/acpica/utxfmutex.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/drivers/acpi/acpica/utxfmutex.c > > b/drivers/acpi/acpica/utxfmutex.c index c016211c35ae..5d20581f4b2f > > 100644 > > --- a/drivers/acpi/acpica/utxfmutex.c > > +++ b/drivers/acpi/acpica/utxfmutex.c > > @@ -150,6 +150,7 @@ acpi_acquire_mutex(acpi_handle handle, acpi_string > > pathname, u16 timeout) > > status = acpi_os_acquire_mutex(mutex_obj->mutex.os_mutex, timeout); > > return (status); > > } > > +ACPI_EXPORT_SYMBOL(acpi_acquire_mutex) > > > > > > /*********************************************************************** > > ******** > > * > > @@ -185,3 +186,4 @@ acpi_status acpi_release_mutex(acpi_handle handle, > > acpi_string pathname) > > acpi_os_release_mutex(mutex_obj->mutex.os_mutex); > > return (AE_OK); > > } > > +ACPI_EXPORT_SYMBOL(acpi_release_mutex) > > -- > > 2.7.4 >