From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH V3] ACPI: Add _DEP(Operation Region Dependencies) support to fix battery issue on the Asus T100TA Date: Mon, 24 Nov 2014 16:27:11 +0100 Message-ID: <1720074.U59stZW2tQ@vostro.rjw.lan> References: <1416748974-24124-1-git-send-email-tianyu.lan@intel.com> <54729A7B.4050007@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <54729A7B.4050007-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Li, Aubrey" Cc: Lan Tianyu , lenb-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org, robert.moore-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, lv.zheng-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, shigorin-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, adamw-cfjF3rc+CpsYNetmKr+vY16hYfS7NtTn@public.gmane.org, jan.brummer-sgYkR6nYkOfYtjvyW6yDsg@public.gmane.org, mika.westerberg-VuQAYsv1563Yd54FQh9/CA@public.gmane.org, linux-acpi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devel-E0kO6a4B6psdnm+yROfE0A@public.gmane.org List-Id: linux-i2c@vger.kernel.org On Monday, November 24, 2014 10:39:55 AM Li, Aubrey wrote: > On 2014/11/23 21:22, Lan Tianyu wrote: > > ACPI 5.0 introduces _DEP to designate device objects that OSPM should > > assign a higher priority in start ordering due to future operation region > > accesses. > > > > On Asus T100TA, ACPI battery info are read from a I2C slave device via > > I2C operation region. Before I2C operation region handler is installed, > > battery _STA always returns 0. There is a _DEP method of designating > > start order under battery device node. > > > > This patch is to implement _DEP feature to fix battery issue on the Asus T100TA. > > Introducing acpi_dep_list and adding dep_unmet count in the struct > > acpi_device. During ACPI namespace scan, create struct acpi_dep_data for a > > valid pair of master (device pointed to by _DEP)/slave(device with _DEP), record > > master's and slave's ACPI handle in it and put it into acpi_dep_list. The dep_unmet > > count will increase by one if there is a device under its _DEP. Driver's probe() should > > return EPROBE_DEFER when find dep_unmet is larger than 0. When I2C operation > > region handler is installed, remove all struct acpi_dep_data on the acpi_dep_list > > whose master is pointed to I2C host controller and decrease slave's dep_unmet. > > When dep_unmet decreases to 0, all _DEP conditions are met and then do acpi_bus_attach() > > for the device in order to resolve battery _STA issue on the Asus T100TA. > > Well, Can we explicitly tied this up with ASUS T100TA in the code? > If I understand correctly, the assumption in the patch is that the > battery device only depends on I2C device, which is true on ASUS T100TA, > but may not on the other platforms. > > This patch does not work on a box I have, on it _DEP contains I2C and GPIO. Does the patch break anything for you? > Device (BATC) > { > Name (_HID, EisaId ("PNP0C0A")) // _HID: Hardware ID > --------snip-------- > Name (_DEP, Package (0x03) // _DEP: Dependencies > { > I2C1, > GPO2, > GPO0 > }) > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.