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* ACPI / tables: Convert initrd table override to table upgrade mechanismLv Zheng2016-04-181-26/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch converts the initrd table override mechanism to the table upgrade mechanism by restricting its usage to the tables released with compatibility and more recent revision. This use case has been encouraged by the ACPI specification: 1. OEMID: An OEM-supplied string that identifies the OEM. 2. OEM Table ID: An OEM-supplied string that the OEM uses to identify the particular data table. This field is particularly useful when defining a definition block to distinguish definition block functions. OEM assigns each dissimilar table a new OEM Table Id. 3. OEM Revision: An OEM-supplied revision number. Larger numbers are assumed to be newer revisions. For OEMs, good practices will ensure consistency when assigning OEMID and OEM Table ID fields in any table. The intent of these fields is to allow for a binary control system that support services can use. Because many support function can be automated, it is useful when a tool can programatically determine which table release is a compatible and more recent revision of a prior table on the same OEMID and OEM Table ID. The facility can now be used by the vendors to upgrade wrong tables for bug fixing purpose, thus lockdep disabling taint is not suitable for it and it should be a default 'y' option to implement the spec encouraged use case. Note that, by implementing table upgrade inside of ACPICA itself, it is possible to remove acpi_table_initrd_override() and tables can be upgraded by acpi_install_table() automatically. Though current ACPICA impelentation hasn't implemented this, this patched changes the table flag setting timing to allow this to be implemented in ACPICA without changing the code here. Documentation of initrd override mechanism is upgraded accordingly. Original-by: Octavian Purdila <octavian.purdila@intel.com> Signed-off-by: Lv Zheng <lv.zheng@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* ACPI: Document ACPI table overriding via initrdThomas Renninger2012-09-301-0/+94
Signed-off-by: Thomas Renninger <trenn@suse.de> Link: http://lkml.kernel.org/r/1349043837-22659-7-git-send-email-trenn@suse.de Cc: Len Brown <lenb@kernel.org> Cc: Robert Moore <robert.moore@intel.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Eric Piel <eric.piel@tremplin-utc.net> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
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