-----Original Message----- From: Nikolaus Voss [mailto:nv@xxxxxxx] Sent: Friday, September 13, 2019 12:44 AM To: Moore, Robert <robert.moore@xxxxxxxxx> Cc: Shevchenko, Andriy <andriy.shevchenko@xxxxxxxxx>; Schmauss, Erik <erik.schmauss@xxxxxxxxx>; Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>; Len Brown <lenb@xxxxxxxxxx>; Jacek Anaszewski <jacek.anaszewski@xxxxxxxxx>; Pavel Machek <pavel@xxxxxx>; Dan Murphy <dmurphy@xxxxxx>; linux-acpi@xxxxxxxxxxxxxxx; devel@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Ferry Toth <ftoth@xxxxxxxxxx>; nikolaus.voss@xxxxxxxxxxxxxxxxxxxxx Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table index Bob, On Thu, 12 Sep 2019, Moore, Robert wrote: > The ability to unload an ACPI table (especially AML tables such as > SSDTs) is in the process of being deprecated in ACPICA -- since it is > also deprecated in the current ACPI specification. This is being done > because of the difficulty of deleting the namespace entries for the > table. FYI, Windows does not properly support this function either. ok, I see it can be a problem to unload an AML table with all it's consequences e.g. with respect to driver unregistering in setups with complex dependencies. It will only work properly under certain conditions - nevertheless acpi_tb_unload_table() is still exported in ACPICA and we should get this working as it worked before. AcpiTbUnloadTable is not exported, it is an internal interface only -- as recognized by the "AcpiTb". I'm not sure that I want to change the interface to AcpiLoadTable just for something that is being deprecated. Already, we throw an ACPI_EXCEPTION if the Unload operator is encountered in the AML byte stream. The same thing with AcpiUnloadParentTable - it is being deprecated. ACPI_EXCEPTION ((AE_INFO, AE_NOT_IMPLEMENTED, "AML Unload operator is not supported")); The API change I request is not directly related to table unloading, it's just that the index of the loaded table is returned for future reference: [...] >> diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h index >> 3845c8fcc94e5..c90bbdc4146a6 100644 >> --- a/include/acpi/acpixf.h >> +++ b/include/acpi/acpixf.h >> @@ -452,7 +452,8 @@ ACPI_EXTERNAL_RETURN_STATUS(acpi_status ACPI_INIT_FUNCTION >> u8 physical)) >> >> ACPI_EXTERNAL_RETURN_STATUS(acpi_status >> - acpi_load_table(struct acpi_table_header *table)) >> + acpi_load_table(struct acpi_table_header *table, >> + u32 *table_idx)) >> >> ACPI_EXTERNAL_RETURN_STATUS(acpi_status >> acpi_unload_parent_table(acpi_handle object)) >> -- >> 2.17.1 >> This allows for a simple fix of the regression and doesn't imply future support for table unloading. Would this be acceptable? Niko
