Hi,

On 3/29/21 3:39 PM, Rafael J. Wysocki wrote:

On Sunday, March 28, 2021 1:20:00 PM CEST Hans de Goede wrote:

quoted

Commit 71da201f38df ("ACPI: scan: Defer enumeration of devices with
_DEP lists") dropped the following 2 lines from acpi_init_device_object():

	/* Assume there are unmet deps until acpi_device_dep_initialize() runs */
	device->dep_unmet = 1;

Leaving the initial value of dep_unmet at the 0 from the kzalloc(). This
causes the acpi_bus_get_status() call in acpi_add_single_object() to
actually call _STA, even though there maybe unmet deps, leading to errors
like these:

[    0.123579] ACPI Error: No handler for Region [ECRM] (00000000ba9edc4c)
               [GenericSerialBus] (20170831/evregion-166)
[    0.123601] ACPI Error: Region GenericSerialBus (ID=9) has no handler
               (20170831/exfldio-299)
[    0.123618] ACPI Error: Method parse/execution failed
               \_SB.I2C1.BAT1._STA, AE_NOT_EXIST (20170831/psparse-550)

Fix this by moving the acpi_scan_dep_init() call done for devices added
during the second pass done by acpi_bus_scan() to inside
acpi_add_single_object(), so that dep_unmet is properly initialized
before the acpi_bus_get_status() call.

I wonder why the change below can't be made instead.

The behavior would be closer to the original then AFAICS.

Right the behavior would be closer to the code before the 2 fase scan
rework. But just actually making sure we have the right value in unmet_dep
a tiny bit earlier seems cleaner to me.

Note that the one acpi_add_single_object() call which actually sets the
new init_dep parameter to true and the previous place of calling
acpi_scan_dep_init() are very close together, here is the code before
this patch:

        acpi_add_single_object(&device, handle, type, sta, !check_dep);
        if (!device)
                return AE_CTRL_DEPTH;

        acpi_scan_init_hotplug(device);
        if (!check_dep)
                acpi_scan_dep_init();

So we are only doing the acpi_scan_dep_init() call a tiny bit earlier
and wrt which locks are being held when it gets called no changes are
made since it is still called as part of the call-graph below
acpi_bus_check_add(), I explicitly checked the locking situation because
that was my one worry with this patch.
		
And this new approach also has the advantage of not setting dep_unmet=1
(and never clearing it) for devices instantiated through:

acpi_bus_register_early_device()
acpi_bus_scan_fixed()
acpi_add_power_resource()

IOW while looking into fixing the regression of the errors being logged
again I tried to do a cleaner fix then last time.

With that said if you prefer the version you suggest let me know and I'll
post a single v2 patch doing things that way.

If you want to go with your suggestion, shall I then add a dep_unmet=0
statement to the 3 mentioned functions which leave it at 1 when going back
to the old way of handling this ?

Regards,

Hans