-----Original Message-----
From: Nikolaus Voss [mailto:n...@vosn.de]
Sent: Friday, September 13, 2019 12:44 AM
To: Moore, Robert <robert.mo...@intel.com>
Cc: Shevchenko, Andriy <andriy.shevche...@intel.com>; Schmauss, Erik
<erik.schma...@intel.com>; Rafael J. Wysocki <r...@rjwysocki.net>; Len Brown
<l...@kernel.org>; Jacek Anaszewski <jacek.anaszew...@gmail.com>; Pavel Machek
<pa...@ucw.cz>; Dan Murphy <dmur...@ti.com>; linux-a...@vger.kernel.org;
de...@acpica.org; linux-kernel@vger.kernel.org; Ferry Toth <ft...@telfort.nl>;
nikolaus.v...@loewensteinmedical.de
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
