tree a131aefb2a66e2dc32e533652a5471ccbc2211e0
parent 488b5ec871191359b9b79262a3d48456dae7ea5f
author Thomas Renninger <trenn@suse.de> 1202196682 -0800
committer Len Brown <len.brown@intel.com> 1202363958 -0500

ACPI: track opregion names to avoid driver resource conflicts.

Small ACPICA extension to be able to store the name of operation regions in osl.c later

In ACPI, AML can define accesses to IO ports and System Memory by Operation
Regions.  Those are not registered as done by PNPACPI using resource templates
(and _CRS/_SRS methods).

The IO ports and System Memory regions may get accessed by arbitrary AML code.
 When native drivers are accessing the same resources bad things can happen
(e.g.  a critical shutdown temperature of 3000 C every 2 months or so).

It is not really possible to register the operation regions via
request_resource, as they often overlap with pnp or other resources (e.g.
statically setup IO resources below 0x100).

This approach stores all Operation Region declarations (IO and System Memory
only) at ACPI table parse time.  It offers a similar functionality like
request_region and let drivers which are known to possibly use the same IO
ports and Memory which are also often used by ACPI (hwmon and i2c) check for
ACPI interference.

A boot parameter acpi_enforce_resources=strict/lax/no is provided, which
is default set to lax:
  - strict: let conflicting drivers fail to load with an error message
  - lax:    let conflicting driver work normal with a warning message
  - no:     no functional change at all
Depending on the feedback and the kind of interferences we see, this
should be set to strict at later time.

Goal of this patch set is:
  - Identify ACPI interferences in bug reports (very hard to reproduce
    and to identify)
  - Find BIOSes for that an ACPI driver should exist for specific HW
    instead of a native one.
  - stability in general

Provide acpi_check_{mem_}region.

Drivers can additionally check against possible ACPI interference by also
invoking this shortly before they call request_region.
If -EBUSY is returned, the driver must not load.
Use acpi_enforce_resources=strict/lax/no options to:
  - strict: let conflicting drivers fail to load with an error message
  - lax:    let conflicting driver work normal with a warning message
  - no:     no functional change at all

Cc: "Mark M. Hoffman" <mhoffman@lightlink.com>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>