Messages in this thread Patch in this message |  | | Date | Fri, 13 Dec 2013 14:17:32 +0900 | From | Yasuaki Ishimatsu <> | Subject | Re: [PATCH 7/10] ACPI / hotplug: Move container-specific code out of the core |
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(2013/12/13 13:56), Rafael J. Wysocki wrote: > On Friday, December 13, 2013 11:56:32 AM Yasuaki Ishimatsu wrote: >> Hi Rafael, > > Hi, > >> Please share your more detailed idea. I started to implement the following >> idea. But the idea has one problem. >> >>>>> The eject work flow can be: >>>>> (1) an eject event occurs, >>>>> (2) the container "physical" device fails offline in acpi_scan_hot_remove() >>>>> emmitting, say, KOBJ_CHANGE for the "physical" device, >>>>> (3) user space notices the KOBJ_CHANGE and does the cleanup as needed, >>>>> (4) user space changes the "physical" container device flag controlling >>>>> offline to 0, >>>>> (5) user space uses the sysfs "eject" attribute of the ACPI container object >>>>> to finally eject the container, >>>>> (6) the offline in acpi_scan_hot_remove() is now successful, because the >>>>> flag controlling it has been set to 0 in step (4), >>>>> (7) the "physical" container device goes away before executing _EJ0, >>>>> (8) the container is ejected. >> >> I want to emit KOBJ_CHANGE before offlining devices on container device at (2). >> But acpi_scan_hot_remove() offlines devices on container device at first. >> So when offline container device, devices on container has been offlined. >> >> Thus the idea cannot fulfill my necessary feature. > > Well, in that case we need to treat containers in a special way at the ACPI > level. Which is a bit unfortunate so to speak. > > To that end I'd try to add a new flag to struct acpi_hotplug_profile, say > .verify_offline, such that if set, it would cause acpi_scan_hot_remove() to > check if all of the "physical" companions of the top-level device are offline > to start with, and if not, it would just emit KOBJ_CHANGE for the companions > that are not offline and bail out. > > So the above algorithm would become: > > (1) an eject event occurs, > (2) acpi_scan_hot_remove() checks the verify_offline flag in the target device's > scan_handler structure, > (3) if set (it would always be set for containers), acpi_scan_hot_remove() > checks the status of the target device's "physical" companions; if at least > one of them is offline, KOBJ_CHANGE is emitted for that "physical" device, > and acpi_scan_hot_remove() returns, [I guess we can just emit KOBJ_CHANGE > for the first companion that is not offline at this point.] > (4) user space notices the KOBJ_CHANGE and does the cleanup as needed; in the > process it carries out the offline operation for the container's "physical" > companion (there's only one such companion for each container), [That > operation for the container itself is trivial, but to succeed it requires > all devices below the container to be taken offline in advance.] > (5) user space uses the sysfs "eject" attribute of the ACPI container object > to finally eject the container, > (6) acpi_scan_hot_remove() is now successful, because the container's "physical" > companion is now offline, > (7) the "physical" container device goes away before executing _EJ0, > (8) the container is ejected. > > I think that should work for you.
This idea seems to same as your previous work. http://lkml.org/lkml/2013/2/23/97
How about add autoremove flag into acpi_hotplug_profile and check it as follow:
--- drivers/acpi/scan.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 5383c81..c43d110 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -409,6 +409,11 @@ static void acpi_hotplug_notify_cb(acpi_handle handle, u32 type, void *data) ost_code = ACPI_OST_SC_EJECT_NOT_SUPPORTED; goto err_out; } + if (!handler->hotplug.autoremove) { + kobject_uevent(&device->dev.kobj, KOBJ_CHANGE); + ost_code = ACPI_OST_SC_EJECT_NON_SPECIFIC_FAILURE; + goto err_out; + } acpi_evaluate_hotplug_ost(handle, ACPI_NOTIFY_EJECT_REQUEST, ACPI_OST_SC_EJECT_IN_PROGRESS, NULL); break; Adding the check into "acpi_hotplug_notify_cb()", user need not change the flag for removing container device by "sysfs eject".
Thanks, Yasuaki Ishimatsu
> > Thanks, > Rafael >
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