From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hanjun Guo Subject: Re: [PATCH 1/5] ACPICA: Add acpi_dev_present Date: Tue, 24 Nov 2015 22:54:35 +0800 Message-ID: <56547A2B.8030401@linaro.org> References: <20151123233234.GA26361@wunner.de> <5653EA53.8040909@huawei.com> <2460979.tXaWt9xg5Q@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <2460979.tXaWt9xg5Q@vostro.rjw.lan> Sender: linux-acpi-owner@vger.kernel.org To: "Rafael J. Wysocki" , Hanjun Guo Cc: Lukas Wunner , "Moore, Robert" , "linux-acpi@vger.kernel.org" , "devel@acpica.org" , "platform-driver-x86@vger.kernel.org" , Darren Hart , Corentin Chary , "Lee, Chun-Yi" , "alsa-devel@alsa-project.org" , Takashi Iwai , Hui Wang , Mark Brown , "Zheng, Lv" , David Box List-Id: alsa-devel@alsa-project.org On 11/24/2015 10:22 PM, Rafael J. Wysocki wrote: > On Tuesday, November 24, 2015 12:40:51 PM Hanjun Guo wrote: >> On 2015/11/24 7:32, Lukas Wunner wrote: >>> Hi Robert, >>> >>> On Mon, Nov 23, 2015 at 10:22:27PM +0000, Moore, Robert wrote: >>>>>> acpi_dev_present >>>> Do you really want to be walking the ACPICA namespace for every call? >>> That's what the drivers currently do. Typically this is called only once >>> on initialization by the driver's ->probe callback. >>> >>> What did you have in mind instead, cache the result? Or store the HIDs >>> in the namespace in a hash that can be queried faster? >> >> Will those drivers be loaded before the acpi namespace is scanned? if not, I think >> those IDs already cached, in acpi_init_device_object(), >> >> INIT_LIST_HEAD(&device->pnp.ids); >> ... >> acpi_set_pnp_ids(handle, &device->pnp, type); >> >> please see API acpi_device_hid(), so I think you can introduce a API with >> acpi_device and HID passed as arguments in scan.c > > I'd prefer that to go to utils.c to be honest, even if the namespace needs to > be walked. I agree, utils.c is the better place to go. Thanks Hanjun