[lkml]   [2019]   [Sep]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [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 []
>> Sent: Friday, September 13, 2019 12:44 AM
>> To: Moore, Robert <>
>> Cc: Shevchenko, Andriy <>; Schmauss, Erik <>; Rafael J. Wysocki <>; Len Brown <>; Jacek Anaszewski <>; Pavel Machek <>; Dan Murphy <>;;;; Ferry Toth <>;
>> 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 <>
> 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

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.
>> "AML Unload operator is not supported"));

 \ /
  Last update: 2019-09-13 18:56    [W:0.061 / U:10.832 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site