RE: [PATCH v2 0/5] ACPI: Do not call _STA on battery devices with unmet dependencies

From: "Moore, Robert" <robert.moore@intel.com>
To: Hans de Goede <hdegoede@redhat.com>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	"linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
	"Schmauss, Erik" <erik.schmauss@intel.com>,
	"Box, David E" <david.e.box@intel.com>
Cc: Len Brown <lenb@kernel.org>, Bjorn Helgaas <bhelgaas@google.com>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	"devel@acpica.org" <devel@acpica.org>
Subject: RE: [PATCH v2 0/5] ACPI: Do not call _STA on battery devices with unmet dependencies
Date: Wed, 14 Feb 2018 15:28:07 +0000	[thread overview]
Message-ID: <94F2FBAB4432B54E8AACC7DFDE6C92E3B7572CE8@ORSMSX110.amr.corp.intel.com> (raw)
In-Reply-To: <a62364ba-7b79-6bb0-20a3-c66cb166e923@redhat.com>

> -----Original Message-----
> From: Hans de Goede [mailto:hdegoede@redhat.com]
> Sent: Wednesday, February 14, 2018 2:33 AM
> To: Moore, Robert <robert.moore@intel.com>; Rafael J. Wysocki
> <rjw@rjwysocki.net>; linux-acpi@vger.kernel.org; Schmauss, Erik
> <erik.schmauss@intel.com>; Box, David E <david.e.box@intel.com>
> Cc: Len Brown <lenb@kernel.org>; Bjorn Helgaas <bhelgaas@google.com>;
> linux-pci@vger.kernel.org; devel@acpica.org
> Subject: Re: [PATCH v2 0/5] ACPI: Do not call _STA on battery devices
> with unmet dependencies
> 
> Hi,
> 
> On 08-02-18 18:34, Moore, Robert wrote:
> >
> >
> >>> The last one needs to go in via ACPICA anyway or we'll need to carry
> >>> a Linux-specific replacement for acpi_get_object_info().
> >>
> >> Ack, I'm discussing how to proceed with this with the ACPICA people.
> >>
> >> Regards,
> >>
> >> Hans
> >
> >
> > I normally don't like to change external interfaces (the biggest
> reason being the sheer number of different OS vendors that use ACPICA),
> but in this case, I feel it may be OK. This interface is probably not
> heavily used, and there is precedent for this when the invocation of
> _SUB was removed.
> >
> > On the other hand, I think I saw it mentioned that Linux calls this
> interface only once, is this correct?
> 
> More or less, Linux calls it once when enumerating all the devices and a
> few ACPI drivers call it again to get some extra info they need.
> 
> > If so, perhaps it would be easiest to simply remove this call and use
> direct control method invocations to obtain the desired data.
> 
> If we go this route we would probably end up copying the function, since
> as said several drivers use it too.
> 
> > If we go ahead and make this change to ACPICA: I have not seen the
> patch, but please make sure that all vestiges of this are removed. This
> includes all invocations within ACPICA that examine the result of the
> _STA invocation, the CurrentStatus field of ACPI_DEVICE_INFO, the
> ACPI_VALID_STA flag, etc.
> 
> The patch already does that:
> 
> https://patchwork.kernel.org/patch/10186195/
> 

Of course, we will need the ACPICA version of the patch, not the "linuxized" version.
Bob

> Regards,
> 
> Hans
> 