Hi,
On 19-01-18 22:03, Schmauss, Erik wrote:
-----Original Message-----
From: linux-acpi-owner@xxxxxxxxxxxxxxx [mailto:linux-acpi-
owner@xxxxxxxxxxxxxxx] On Behalf Of Bjorn Helgaas
Sent: Thursday, January 18, 2018 11:11 AM
To: Hans de Goede <hdegoede@xxxxxxxxxx>
Cc: Rafael J . Wysocki <rjw@xxxxxxxxxxxxx>; Len Brown <lenb@xxxxxxxxxx>;
Bjorn Helgaas <bhelgaas@xxxxxxxxxx>; Moore, Robert
<robert.moore@xxxxxxxxx>; Zheng, Lv <lv.zheng@xxxxxxxxx>; linux-
acpi@xxxxxxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx; devel@xxxxxxxxxx
Subject: Re: ACPI: Do not call _STA on battery devices with unmet dependencies
On Thu, Jan 18, 2018 at 05:03:55PM +0100, Hans de Goede wrote:
Hi Hans,
Hi All,
The ACPI code already contains quite a bit of code to not bind the
ACPI-battery until all deps for an ACPI battery device have been met,
but on some devices calling _STA before all deps are met is a problem
too because the _STA method uses an i2c OpRegion there.
Could you explain why _STA method using an I2C OpRegion is problematic?
It is problematic if we call the _STA method before the handler for
the OpRegion has been installed, this series delays / avoids calling
_STA before the OpRegion has been installed.
Regards,
Hans
Thanks,
Erik
Here is the DSDT of the device I'm seeing this on:
https://fedorapeople.org/~jwrdegoede/toshiba-click-mini-dsdt.dsl
This looks like interesting info, but (a) this link isn't mentioned in the actual
patches, and (b) it's conceivable that fedorapeople.org could go away someday.
If this were a PCI series, I would suggest opening a report at bugzilla.kernel.org,
attaching the DSL there, and including the link in the patch changelog.
This series modifies the kernel to not call _STA until all deps are
met, mirroring the binding behavior of the battery driver.
Without this series a total of 32 ACPI errors get printend to the
console on boot, there are 4 errors per _STA call, 2 battery devices
on this system and 4 _STA calls per battery device.
The first commit is a preparation commit for making the ACPICA changes
in the 4th commit, this commit is necessary to not break things after
the ACPICA changes.
The second commit modifies acpi_bus_get_status to not call _STA on
battery devices until all deps are met. This fixes 2 of the 4 too
early _STA calls triggering these errors.
The third commit makes the device instantiation code use
acpi_bus_get_status instead of acpi_bus_get_status_handle so that the
code to get the initial status also does not makes 1 too early _STA call.
The fourth commit changes the ACPICA acpi_get_object_info function to
not call _STA. Only 1 user (which is fixed in the first commit) cares
about acpi_device_info.current_status. And the ACPICA code has this
comment:
* Note: This interface is intended to be used during the initial
device
* discovery namespace traversal. Therefore, no complex methods can be
* executed, especially those that access operation regions.
Therefore, do
* not add any additional methods that could cause problems in this area.
* Because of this reason support for the following methods has been
removed:
* this was the fate of the _SUB method which was found to cause such
* problems and was removed (11/2015).
The described problems with the _SUB method clearly also apply to the
_STA method, so removing it from acpi_get_object_info seems like it is
the right thing to do here. This too fixes 1 too early _STA call, so
that with all
4 patches in place we've fixed all 4 too early _STA calls.
Regards,
Hans
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