How about this:
Go back to using acpi_tb_install_and_load_table(), but then call
acpi_ns_initialize_objects afterwards This is what acpi_load_table does.
ACPI_INFO (("Host-directed Dynamic ACPI Table Load:"));
Status = AcpiTbInstallAndLoadTable (ACPI_PTR_TO_PHYSADDR (Table),
ACPI_TABLE_ORIGIN_EXTERNAL_VIRTUAL, FALSE, &TableIndex);
if (ACPI_SUCCESS (Status))
{
/* Complete the initialization/resolution of new objects */
AcpiNsInitializeObjects ();
}
-----Original Message-----
From: Nikolaus Voss <[email protected]>
Sent: Monday, September 23, 2019 2:05 AM
To: Moore, Robert <[email protected]>
Cc: Ferry Toth <[email protected]>; Shevchenko, Andriy
<[email protected]>; Schmauss, Erik <[email protected]>; Rafael
J. Wysocki <[email protected]>; Len Brown <[email protected]>; Jacek Anaszewski
<[email protected]>; Pavel Machek <[email protected]>; Dan Murphy
<[email protected]>; [email protected]; [email protected];
[email protected]; Jan Kiszka <[email protected]>
Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table index
On Thu, 19 Sep 2019, Moore, Robert wrote:
>
>
> -----Original Message-----
> From: Nikolaus Voss [mailto:[email protected]]
> Sent: Wednesday, September 18, 2019 7:32 AM
> To: Moore, Robert <[email protected]>
> Cc: Ferry Toth <[email protected]>; Shevchenko, Andriy
> <[email protected]>; Schmauss, Erik
> <[email protected]>; Rafael J. Wysocki <[email protected]>; Len
> Brown <[email protected]>; Jacek Anaszewski
> <[email protected]>; Pavel Machek <[email protected]>; Dan Murphy
> <[email protected]>; [email protected]; [email protected];
> [email protected]; Jan Kiszka <[email protected]>
> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table index
>
> On Wed, 18 Sep 2019, Moore, Robert wrote:
>>
>>
>> -----Original Message-----
>> From: Nikolaus Voss [mailto:[email protected]]
>> Sent: Monday, September 16, 2019 2:47 AM
>> To: Moore, Robert <[email protected]>
>> Cc: Ferry Toth <[email protected]>; Shevchenko, Andriy
>> <[email protected]>; Schmauss, Erik
>> <[email protected]>; Rafael J. Wysocki <[email protected]>; Len
>> Brown <[email protected]>; Jacek Anaszewski
>> <[email protected]>; Pavel Machek <[email protected]>; Dan Murphy
>> <[email protected]>; [email protected]; [email protected];
>> [email protected]; Jan Kiszka <[email protected]>
>> Subject: RE: [PATCH] ACPICA: make acpi_load_table() return table
>> index
>>
>> On Fri, 13 Sep 2019, Moore, Robert wrote:
>>>
>>>
>>> -----Original Message-----
>>> From: Ferry Toth [mailto:[email protected]]
>>> Sent: Friday, September 13, 2019 9:48 AM
>>> To: Shevchenko, Andriy <[email protected]>; Moore, Robert
>>> <[email protected]>
>>> Cc: Nikolaus Voss <[email protected]>; Schmauss, Erik
>>> <[email protected]>; Rafael J. Wysocki <[email protected]>;
>>> Len Brown <[email protected]>; Jacek Anaszewski
>>> <[email protected]>; Pavel Machek <[email protected]>; Dan
>>> Murphy <[email protected]>; [email protected];
>>> [email protected]; [email protected];
>>> [email protected];
>>> Jan Kiszka <[email protected]>
>>> Subject: Re: [PATCH] ACPICA: make acpi_load_table() return table
>>> index
>>>
>>> Hello all,
>>>
>>> Sorry to have sent our message with cancelled e-mail address. I have
>>> correct this now.
>>>
>>> Op 13-09-19 om 17:12 schreef Shevchenko, Andriy:
>>>> On Fri, Sep 13, 2019 at 05:20:21PM +0300, Moore, Robert wrote:
>>>>> -----Original Message-----
>>>>> From: Nikolaus Voss [mailto:[email protected]]
>>>>> Sent: Friday, September 13, 2019 12:44 AM
>>>>> To: Moore, Robert <[email protected]>
>>>>> Cc: Shevchenko, Andriy <[email protected]>; Schmauss,
>>>>> Erik <[email protected]>; Rafael J. Wysocki
>>>>> <[email protected]>; Len Brown <[email protected]>; Jacek Anaszewski
>>>>> <[email protected]>; Pavel Machek <[email protected]>; Dan
>>>>> Murphy <[email protected]>; [email protected];
>>>>> [email protected]; [email protected]; Ferry Toth
>>>>> <[email protected]>; [email protected]
>>>>> 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".
>>>>
>>>> In Linux it became a part of ABI when the
>>>>
>>>> commit 772bf1e2878ecfca0d1f332071c83e021dd9cf01
>>>> Author: Jan Kiszka <[email protected]>
>>>> Date: Fri Jun 9 20:36:31 2017 +0200
>>>>
>>>> ACPI: configfs: Unload SSDT on configfs entry removal
>>>>
>>>> appeared in the kernel.
>>>
>>> And the commit message explains quite well why it is an important feature:
>>>
>>> "This allows to change SSDTs without rebooting the system.
>>> It also allows to destroy devices again that a dynamically loaded SSDT
>>> created.
>>>
>>> The biggest problem AFAIK is that under linux, many drivers cannot be
>>> unloaded. Also, there are many race conditions as the namespace entries
>>> "owned" by an SSDT being unloaded are deleted (out from underneath a
>>> driver).
>>>
>>> This is widely similar to the DT overlay behavior."
>>>
>>>>> 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"));
>>
>> Bob, what is your suggestion to fix the regression then?
>>
>> We could revert acpi_configfs.c to use
>> acpi_tb_install_and_load_table() instead of acpi_load_table(),
>> leaving loaded APCI objects uninitalized, but at least, unloading will work
>> again.
>>
>> I guess my next question is: why do you want to unload a table in the
>> first place?
>
> Because it worked before and there are people who rely on it. If it's
> deprecated there should be a user notification and a reasonable
> end-of-life timeline to give these users a chance to develop an
> alternative solution.
>
> So, I still don't understand why this no longer works. We did not make
> any purposeful changes in this area - AFAIK. Bob
It's because the acpi_configfs driver formerly used
acpi_tb_install_and_load_table() which returns the table index, but doesn't
resolve the references. It now uses acpi_load_table() which resolves the
references, but doesn't return the table index, so unloading doesn't work any
more.
>
> Niko
>
>>
>>
>> Do we have any other options?
>>
>> Niko
>>
>
