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From: Nikolaus Voss <nv@vosn.de>
To: "Shevchenko, Andriy" <andriy.shevchenko@intel.com>
Cc: "Schmauss, Erik" <erik.schmauss@intel.com>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Len Brown <lenb@kernel.org>,
	"Moore, Robert" <robert.moore@intel.com>,
	Jacek Anaszewski <jacek.anaszewski@gmail.com>,
	Pavel Machek <pavel@ucw.cz>, Dan Murphy <dmurphy@ti.com>,
	"linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
	"devel@acpica.org" <devel@acpica.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] ACPI: Resolve objects on host-directed table loads
Date: Thu, 12 Sep 2019 10:05:20 +0200 (CEST)
Message-ID: <alpine.DEB.2.20.1909120947190.4439@fox.voss.local> (raw)
In-Reply-To: <20190906174605.GY2680@smile.fi.intel.com>

[-- Attachment #1: Type: text/plain, Size: 3840 bytes --]

On Fri, 6 Sep 2019, Shevchenko, Andriy wrote:
> On Wed, Sep 04, 2019 at 09:20:03AM +0200, Nikolaus Voss wrote:
>> On Fri, 30 Aug 2019, Shevchenko, Andriy wrote:
>>> On Fri, Aug 16, 2019 at 01:57:26PM +0200, Nikolaus Voss wrote:
>>>> On Wed, 14 Aug 2019, Schmauss, Erik wrote:
>>>>>> -----Original Message-----
>>>>>> From: Shevchenko, Andriy
>>>>>> Sent: Wednesday, August 14, 2019 11:51 AM
>>>>>> To: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
>>>>>> Cc: Rafael J. Wysocki <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>;
>>>>>> Moore, Robert <robert.moore@intel.com>; Schmauss, Erik
>>>>>> <erik.schmauss@intel.com>; Jacek Anaszewski <jacek.anaszewski@gmail.com>;
>>>>>> Pavel Machek <pavel@ucw.cz>; Dan Murphy <dmurphy@ti.com>; Thierry
>>>>>> Reding <thierry.reding@gmail.com>; linux-acpi@vger.kernel.org;
>>>>>> devel@acpica.org; linux-leds@vger.kernel.org; linux-pwm@vger.kernel.org
>>>>>> Subject: Re: [PATCH 1/3] ACPI: Resolve objects on host-directed table loads
>>>>>>
>>>>>> On Wed, May 29, 2019 at 02:18:20PM +0200, Nikolaus Voss wrote:
>>>>>>> If an ACPI SSDT overlay is loaded after built-in tables have been
>>>>>>> loaded e.g. via configfs or efivar_ssdt_load() it is necessary to
>>>>>>> rewalk the namespace to resolve references. Without this, relative and
>>>>>>> absolute paths like ^PCI0.SBUS or \_SB.PCI0.SBUS are not resolved
>>>>>>> correctly.
>>>>>>>
>>>>>>> Make configfs load use the same method as efivar_ssdt_load().
>>>>>>
>>>>>> This patch brought a regression (bisect log below).
>>>>>> Now I'm unable to unload the table which was working before.
>>>>>>
>>>>>> Reverting (manual, due to ACPICA changes) helps.
>>>>>>
>>>>>> Please, consider to revert for this cycle, or fix. I will be glad to test any
>>>>>> proposed fix.
>>>>>
>>>>> We submitted a patch (d1fb5b2f623b1af5a0d2a83d205df1b61f430dc6)
>>>>> in response to this suggestion and I was not aware that this had been applied.
>>>>>
>>>>> Rafael, please revert at least the ACPICA portion of this patch.
>>>>
>>>> As I see it, my ACPICA change is not part of 5.3-rc1 any more. Reverting my
>>>> fix is part of the patch above (d1fb5b2f623b1af5a0d2a83d205df1b61f430dc6)
>>>> which is already applied.
>>>>
>>>> Nevertheless, what is new, is that acpi_ns_initialize_objects() is called in
>>>> acpi_load_table(). This is necessary to resolve the references in the newly
>>>> loaded table. Maybe this prevents the table from being unloaded?
>>>
>>> So, can we do something about it? It's a regression.
>>>
>>> Rafael, Nikolaus?
>>
>> can you describe how you unload the table (from userspace?). I cannot
>> reproduce this regression. I was not aware of any working interface for
>> unloading ACPI tables, I ended up in kexec'ing the kernel for my tests each
>> time I had to unload a table.
>
> Sure.
>
> I have connected an I²C device(s) to my board where I have compiled ACPI tables
> which describes them (more details if you want to know is on [1]).
>
> So, I create a folder in ConfigFS [1,2] and fill it up with SSDT (an *.aml file).
> After this, if I try to remove the folder in ConfigFS followed by table removal
> event, the actual nodes won't be removed, and this messes up with the internal
> representation of the ACPI device tree.
>
> [1]: https://www.kernel.org/doc/html/latest/admin-guide/acpi/ssdt-overlays.html
> [2]: https://htot.github.io/meta-intel-edison/1.3-ACPI-or-not.html#run-time-loading-through-configfs

Thanks, I have reproduced it and the culprit is my acpi_configfs patch 
that now uses acpi_load_table() to have the references resolved.

My proposal would be to have that function return the table index, which 
is needed to unload the table. I'll submit a patch, Andy, could you test 
it in your setup?

Erik/Robert, is it ok to change the acpi_load_table() ACPICA API 
function? It has only a few uses.

Niko

  reply index

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-29 12:18 [PATCH 0/3] PWM framework: add support referencing PWMs from ACPI Nikolaus Voss
2019-05-29 12:18 ` [PATCH 1/3] ACPI: Resolve objects on host-directed table loads Nikolaus Voss
2019-05-30 14:42   ` Dan Murphy
2019-05-31 12:23     ` Pavel Machek
2019-05-31 12:45       ` Dan Murphy
2019-05-31 12:46     ` Dan Murphy
2019-06-03  9:12       ` Nikolaus Voss
2019-08-14 18:50   ` Andy Shevchenko
2019-08-14 20:27     ` Schmauss, Erik
2019-08-16 11:57       ` Nikolaus Voss
2019-08-30 14:53         ` Shevchenko, Andriy
2019-09-04  7:20           ` Nikolaus Voss
2019-09-06 17:46             ` Shevchenko, Andriy
2019-09-12  8:05               ` Nikolaus Voss [this message]
2019-09-12  8:07               ` [PATCH] ACPICA: make acpi_load_table() return table index Nikolaus Voss
2019-09-12 14:19                 ` Moore, Robert
2019-09-12 19:36                   ` Ferry Toth
2019-09-13  7:44                   ` Nikolaus Voss
2019-09-13 14:20                     ` Moore, Robert
2019-09-13 15:12                       ` Shevchenko, Andriy
2019-09-13 16:48                         ` Ferry Toth
2019-09-13 16:48                           ` Ferry Toth
2019-09-13 17:40                           ` Moore, Robert
2019-09-13 19:56                             ` Rafael J. Wysocki
2019-09-16  9:46                             ` Nikolaus Voss
2019-09-18 14:13                               ` Moore, Robert
2019-09-18 14:31                                 ` Nikolaus Voss
2019-09-19  8:13                 ` Rafael J. Wysocki
2019-05-29 12:18 ` [PATCH 2/3] PWM framework: add support referencing PWMs from ACPI Nikolaus Voss
2019-05-30 14:54   ` Dan Murphy
2019-05-31 12:24     ` Pavel Machek
2019-06-03  9:27     ` Nikolaus Voss
2019-05-29 12:18 ` [PATCH 3/3] leds-pwm.c: support ACPI via firmware-node framework Nikolaus Voss
2019-05-30 15:14   ` Dan Murphy
2019-06-03  9:44     ` Nikolaus Voss

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