-----Original Message----- From: linux-acpi-owner(a)vger.kernel.org [mailto:linux-acpi- owner(a)vger.kernel.org] On Behalf Of Bjorn Helgaas Sent: Thursday, January 18, 2018 11:11 AM To: Hans de Goede <hdegoede(a)redhat.com&gt; Cc: Rafael J . Wysocki <rjw(a)rjwysocki.net&gt;; Len Brown <lenb(a)kernel.org&gt;; Bjorn Helgaas <bhelgaas(a)google.com&gt;; Moore, Robert <robert.moore(a)intel.com&gt;; Zheng, Lv <lv.zheng(a)intel.com&gt;; linux- acpi(a)vger.kernel.org; linux-pci(a)vger.kernel.org; devel(a)acpica.org 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 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.

> > 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 > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" > in the body of a message to majordomo(a)vger.kernel.org More majordomo > info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html