From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753147AbaCJCpK (ORCPT ); Sun, 9 Mar 2014 22:45:10 -0400 Received: from mga01.intel.com ([192.55.52.88]:26487 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752781AbaCJCpH (ORCPT ); Sun, 9 Mar 2014 22:45:07 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.97,621,1389772800"; d="scan'208";a="495194176" Message-ID: <1394419503.10554.21.camel@rzhang1-mobl4> Subject: Re: [RFC PATCH 6/8] ACPI: use platform bus as the default bus for _HID enumeration From: Zhang Rui To: "Rafael J. Wysocki" Cc: linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, bhelgaas@google.com, matthew.garrett@nebula.com, rafael.j.wysocki@intel.com, dmitry.torokhov@gmail.com Date: Mon, 10 Mar 2014 10:45:03 +0800 In-Reply-To: <6354388.qLqPjcP6yZ@vostro.rjw.lan> References: <1393405874-3266-1-git-send-email-rui.zhang@intel.com> <1393405874-3266-7-git-send-email-rui.zhang@intel.com> <1394380237.9269.31.camel@rzhang1-mobl4> <6354388.qLqPjcP6yZ@vostro.rjw.lan> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2014-03-09 at 19:04 +0100, Rafael J. Wysocki wrote: > On Sunday, March 09, 2014 11:50:37 PM Zhang Rui wrote: > > On Wed, 2014-02-26 at 17:11 +0800, Zhang Rui wrote: > > > Because of the growing demand for enumerating ACPI devices to platform bus, > > > this patch changes the code to enumerate ACPI devices with _HID/_CID to > > > platform bus by default, unless the device already has a scan handler attached. > > > > > > Signed-off-by: Zhang Rui > > > --- > > > drivers/acpi/acpi_platform.c | 28 ---------------------------- > > > drivers/acpi/scan.c | 12 ++++++------ > > > 2 files changed, 6 insertions(+), 34 deletions(-) > > > > > > diff --git a/drivers/acpi/acpi_platform.c b/drivers/acpi/acpi_platform.c > > > index dbfe49e..33376a9 100644 > > > --- a/drivers/acpi/acpi_platform.c > > > +++ b/drivers/acpi/acpi_platform.c > > > @@ -22,24 +22,6 @@ > > > > > > ACPI_MODULE_NAME("platform"); > > > > > > -/* > > > - * The following ACPI IDs are known to be suitable for representing as > > > - * platform devices. > > > - */ > > > -static const struct acpi_device_id acpi_platform_device_ids[] = { > > > - > > > - { "PNP0D40" }, > > > - { "ACPI0003" }, > > > - { "VPC2004" }, > > > - { "BCM4752" }, > > > - > > > - /* Intel Smart Sound Technology */ > > > - { "INT33C8" }, > > > - { "80860F28" }, > > > - > > > - { } > > > -}; > > > - > > > /** > > > * acpi_create_platform_device - Create platform device for ACPI device node > > > * @adev: ACPI device node to create a platform device for. > > > @@ -125,13 +107,3 @@ int acpi_create_platform_device(struct acpi_device *adev, > > > kfree(resources); > > > return 1; > > > } > > > - > > > -static struct acpi_scan_handler platform_handler = { > > > - .ids = acpi_platform_device_ids, > > > - .attach = acpi_create_platform_device, > > > -}; > > > - > > > -void __init acpi_platform_init(void) > > > -{ > > > - acpi_scan_add_handler(&platform_handler); > > > -} > > > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c > > > index 5967338..61af32e 100644 > > > --- a/drivers/acpi/scan.c > > > +++ b/drivers/acpi/scan.c > > > @@ -2022,14 +2022,15 @@ static int acpi_scan_attach_handler(struct acpi_device *device) > > > handler = acpi_scan_match_handler(hwid->id, &devid); > > > if (handler) { > > > ret = handler->attach(device, devid); > > > - if (ret > 0) { > > > + if (ret > 0) > > > device->handler = handler; > > > - break; > > > - } else if (ret < 0) { > > > - break; > > > - } > > > + if (ret) > > > + goto end; > > > } > > > } > > > +end: > > > + if (!list_empty(&device->pnp.ids) && !device->handler) > > > + acpi_create_platform_device(device, NULL); > > > > I just found a big problem in this proposal, which affects all the > > optional scan handlers. > > What do you mean by "optional"? Such that can be compiled out? > yes. > > The problem is that, if we disable a scan handler, platform device nodes > > would be created instead by the code above, because there is no scan > > handler attached for those ACPI nodes. > > If "we disable a scan handled" means "we compile it out", I'm not sure > why creating platform devices for the device objects in question will > be incorrect? > take lpss scan handler and 80860F0A device for example, acpi_lpss_create_device() would invoke lpss_uart_setup() first and then register 80860F0A as a platform device. if the lpss scan handler is compiled out, we would do nothing but register a platform device directly, thus the dw8250_platform_driver driver is still loaded, but probably breaks. IMO, we should either have a full functional platform device (if the scan handler is compiled in) or nothing (if the scan handler is compiled out). thanks, rui > Rafael > > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html