On Tuesday, March 04, 2014 01:35:00 AM Rafael J. Wysocki wrote: > On 3/4/2014 1:27 AM, Zhang, Rui wrote: > > > >> -----Original Message----- > >> From: Rafael J. Wysocki [mailto:rjw@xxxxxxxxxxxxx] > >> Sent: Tuesday, March 04, 2014 7:23 AM > >> To: Zhang, Rui > >> Cc: linux-acpi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > >> bhelgaas@xxxxxxxxxx; matthew.garrett@xxxxxxxxxx; Wysocki, Rafael J; > >> dmitry.torokhov@xxxxxxxxx > >> Subject: Re: [RFC PATCH 6/8] ACPI: use platform bus as the default bus > >> for _HID enumeration > >> Importance: High > >> > >> On Monday, March 03, 2014 10:11:48 PM Zhang Rui wrote: > >>> On Mon, 2014-03-03 at 00:51 +0100, Rafael J. Wysocki wrote: > >>>> On Wednesday, February 26, 2014 05:11:12 PM 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 <rui.zhang@xxxxxxxxx> > >>>>> --- > >>>>> 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) > >>>> I'm a bit concerned that this check will create platform devices > >> for > >>>> too many ACPI device objects. > >>> agreed. there are some devices created unexpected by this patch, e.g. > >>> on my test machine, I can see > >>> > >>> /sys/bus/platform/devices/LNXSYSTM:00 (ACPI system bus/root node) > >>> /sys/bus/platform/devices/PNP0000:00 (PIC) > >>> /sys/bus/platform/devices/PNP0100:00 (system timer?) > >>> > >>>> Shouldn't we require that _HID or at least _CID is present for > >>>> that? > >>>> > >>> I do not think so. > >>> only devices that invoke acpi_add_ids() may have pnp.ids but no > >>> _HID/_CID, right? > >>> I did a check in the code, those devices include: > >> Well, I did that too. > >> > >>> ACPI root node > >>> ACPI video > >>> ACPI bay > >>> ACPI dock > >>> IBM SMBus > >>> ACPI Power resource > >>> ACPI processor > >>> ACPI thermal > >>> ACPI fixed power/sleep button > >>> > >>> IMO, only the ACPI root node, ACPI power resource, possibly ACPI > >>> processor are the ones that we do not want to see in platform bus. > >> No, we don't want any of them. So pretty much as I said, only if > >> _HID/_CID is present, please? > >> > > Why? We will convert the drivers for most of those devices from ACPI bus to platform bus sooner or later. > > We need to see them in platform bus... > > No, we don't. > > I'm not sure about IBM SMBus to be honest, but as for the rest: > > Why would we want one for the ACPI root? > > And for video? Those things are PCI usually devices anyway and we just > add "artificial" HIDs for them. > > ACPI docks and bays are handled by the dock driver which creates > platform devices for them already if needed and we don't want duplicates > there. > > ACPI processor has its own scan handler that binds those objects to > system devices. > > Power resources - no need. > > Do we need platform devices for ACPI thermal zones? > > Yes, we will need them for fixed buttons, but that's a special case anyway. So, why don't we add an ACPI device object flag, say hid_device, such that if set, the ACPI core will create a struct platform device for that device object. Then, we can set hid_device for buttons and other stuff we care about. Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
