Re: [PATCH 1/3] ACPI: Resolve objects on host-directed table loads

Re: [PATCH 1/3] ACPI: Resolve objects on host-directed table loads

[Andy Shevchenko]

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.


git bisect start
# good: [0ecfebd2b52404ae0c54a878c872bb93363ada36] Linux 5.2
git bisect good 0ecfebd2b52404ae0c54a878c872bb93363ada36
# bad: [5f9e832c137075045d15cd6899ab0505cfb2ca4b] Linus 5.3-rc1
git bisect bad 5f9e832c137075045d15cd6899ab0505cfb2ca4b
# bad: [e786741ff1b52769b044b7f4407f39cd13ee5d2d] Merge tag 'staging-5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging
git bisect bad e786741ff1b52769b044b7f4407f39cd13ee5d2d
# bad: [8f6ccf6159aed1f04c6d179f61f6fb2691261e84] Merge tag 'clone3-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
git bisect bad 8f6ccf6159aed1f04c6d179f61f6fb2691261e84
# good: [ed63b9c873601ca113da5c7b1745e3946493e9f3] Merge tag 'media/v5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
git bisect good ed63b9c873601ca113da5c7b1745e3946493e9f3
# bad: [4b4704520d97b74e045154fc3b844b73ae4e7ebd] Merge tag 'acpi-5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
git bisect bad 4b4704520d97b74e045154fc3b844b73ae4e7ebd
# good: [e3303268f9cfa4eb7c2217df471417d4327109fd] ASoC: soc-core: don't use soc_find_component() at snd_soc_find_dai()
git bisect good e3303268f9cfa4eb7c2217df471417d4327109fd
# good: [3c53c6255d598db7084c5c3d7553d7200e857818] Merge tag 'asoc-v5.3' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus
git bisect good 3c53c6255d598db7084c5c3d7553d7200e857818
# good: [4cdd5f9186bbe80306e76f11da7ecb0b9720433c] Merge tag 'sound-5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
git bisect good 4cdd5f9186bbe80306e76f11da7ecb0b9720433c
# good: [13b06b78c772d64e2207e4a5a5329856fe2bf241] Merge branches 'pm-opp', 'pm-misc', 'pm-avs' and 'pm-tools'
git bisect good 13b06b78c772d64e2207e4a5a5329856fe2bf241
# good: [cf2d213e49fdf47e4c10dc629a3659e0026a54b8] Merge tag 'pm-5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
git bisect good cf2d213e49fdf47e4c10dc629a3659e0026a54b8
# bad: [02a93f35f57fe5d4d1bac0ac8496884235e2fd2e] ACPICA: Update version to 20190703
git bisect bad 02a93f35f57fe5d4d1bac0ac8496884235e2fd2e
# bad: [d4ca763eed3bcc227f220beb11ff4eb2fa548755] Merge ACPI tables handling changes for v5.3.
git bisect bad d4ca763eed3bcc227f220beb11ff4eb2fa548755
# bad: [d06c47e3dd07fdf3f07e8fc45f2ce655e9b295c5] ACPI: configfs: Resolve objects on host-directed table loads
git bisect bad d06c47e3dd07fdf3f07e8fc45f2ce655e9b295c5
# good: [c78fea61f0c1f8568fbbb36ac3d1e1c85a903ae4] ACPI: tables: Allow BGRT to be overridden
git bisect good c78fea61f0c1f8568fbbb36ac3d1e1c85a903ae4
# first bad commit: [d06c47e3dd07fdf3f07e8fc45f2ce655e9b295c5] ACPI: configfs: Resolve objects on host-directed table loads

-- 
With Best Regards,
Andy Shevchenko

RE: [PATCH 1/3] ACPI: Resolve objects on host-directed table loads

[Schmauss, Erik]

> -----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.

Thanks,
Erik
> 
> 
> git bisect start
> # good: [0ecfebd2b52404ae0c54a878c872bb93363ada36] Linux 5.2 git bisect
> good 0ecfebd2b52404ae0c54a878c872bb93363ada36
> # bad: [5f9e832c137075045d15cd6899ab0505cfb2ca4b] Linus 5.3-rc1 git
> bisect bad 5f9e832c137075045d15cd6899ab0505cfb2ca4b
> # bad: [e786741ff1b52769b044b7f4407f39cd13ee5d2d] Merge tag 'staging-
> 5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging
> git bisect bad e786741ff1b52769b044b7f4407f39cd13ee5d2d
> # bad: [8f6ccf6159aed1f04c6d179f61f6fb2691261e84] Merge tag 'clone3-v5.3'
> of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
> git bisect bad 8f6ccf6159aed1f04c6d179f61f6fb2691261e84
> # good: [ed63b9c873601ca113da5c7b1745e3946493e9f3] Merge tag
> 'media/v5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-
> media
> git bisect good ed63b9c873601ca113da5c7b1745e3946493e9f3
> # bad: [4b4704520d97b74e045154fc3b844b73ae4e7ebd] Merge tag 'acpi-5.3-
> rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
> git bisect bad 4b4704520d97b74e045154fc3b844b73ae4e7ebd
> # good: [e3303268f9cfa4eb7c2217df471417d4327109fd] ASoC: soc-core: don't
> use soc_find_component() at snd_soc_find_dai() git bisect good
> e3303268f9cfa4eb7c2217df471417d4327109fd
> # good: [3c53c6255d598db7084c5c3d7553d7200e857818] Merge tag 'asoc-
> v5.3' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-
> linus git bisect good 3c53c6255d598db7084c5c3d7553d7200e857818
> # good: [4cdd5f9186bbe80306e76f11da7ecb0b9720433c] Merge tag 'sound-
> 5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
> git bisect good 4cdd5f9186bbe80306e76f11da7ecb0b9720433c
> # good: [13b06b78c772d64e2207e4a5a5329856fe2bf241] Merge branches
> 'pm-opp', 'pm-misc', 'pm-avs' and 'pm-tools'
> git bisect good 13b06b78c772d64e2207e4a5a5329856fe2bf241
> # good: [cf2d213e49fdf47e4c10dc629a3659e0026a54b8] Merge tag 'pm-5.3-
> rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
> git bisect good cf2d213e49fdf47e4c10dc629a3659e0026a54b8
> # bad: [02a93f35f57fe5d4d1bac0ac8496884235e2fd2e] ACPICA: Update
> version to 20190703 git bisect bad
> 02a93f35f57fe5d4d1bac0ac8496884235e2fd2e
> # bad: [d4ca763eed3bcc227f220beb11ff4eb2fa548755] Merge ACPI tables
> handling changes for v5.3.
> git bisect bad d4ca763eed3bcc227f220beb11ff4eb2fa548755
> # bad: [d06c47e3dd07fdf3f07e8fc45f2ce655e9b295c5] ACPI: configfs: Resolve
> objects on host-directed table loads git bisect bad
> d06c47e3dd07fdf3f07e8fc45f2ce655e9b295c5
> # good: [c78fea61f0c1f8568fbbb36ac3d1e1c85a903ae4] ACPI: tables: Allow
> BGRT to be overridden git bisect good
> c78fea61f0c1f8568fbbb36ac3d1e1c85a903ae4
> # first bad commit: [d06c47e3dd07fdf3f07e8fc45f2ce655e9b295c5] ACPI:
> configfs: Resolve objects on host-directed table loads
> 
> --
> With Best Regards,
> Andy Shevchenko
> 

RE: [PATCH 1/3] ACPI: Resolve objects on host-directed table loads

[Nikolaus Voss]

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?

Niko

>
> Thanks,
> Erik
>>
>>
>> git bisect start
>> # good: [0ecfebd2b52404ae0c54a878c872bb93363ada36] Linux 5.2 git bisect
>> good 0ecfebd2b52404ae0c54a878c872bb93363ada36
>> # bad: [5f9e832c137075045d15cd6899ab0505cfb2ca4b] Linus 5.3-rc1 git
>> bisect bad 5f9e832c137075045d15cd6899ab0505cfb2ca4b
>> # bad: [e786741ff1b52769b044b7f4407f39cd13ee5d2d] Merge tag 'staging-
>> 5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging
>> git bisect bad e786741ff1b52769b044b7f4407f39cd13ee5d2d
>> # bad: [8f6ccf6159aed1f04c6d179f61f6fb2691261e84] Merge tag 'clone3-v5.3'
>> of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
>> git bisect bad 8f6ccf6159aed1f04c6d179f61f6fb2691261e84
>> # good: [ed63b9c873601ca113da5c7b1745e3946493e9f3] Merge tag
>> 'media/v5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-
>> media
>> git bisect good ed63b9c873601ca113da5c7b1745e3946493e9f3
>> # bad: [4b4704520d97b74e045154fc3b844b73ae4e7ebd] Merge tag 'acpi-5.3-
>> rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
>> git bisect bad 4b4704520d97b74e045154fc3b844b73ae4e7ebd
>> # good: [e3303268f9cfa4eb7c2217df471417d4327109fd] ASoC: soc-core: don't
>> use soc_find_component() at snd_soc_find_dai() git bisect good
>> e3303268f9cfa4eb7c2217df471417d4327109fd
>> # good: [3c53c6255d598db7084c5c3d7553d7200e857818] Merge tag 'asoc-
>> v5.3' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-
>> linus git bisect good 3c53c6255d598db7084c5c3d7553d7200e857818
>> # good: [4cdd5f9186bbe80306e76f11da7ecb0b9720433c] Merge tag 'sound-
>> 5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
>> git bisect good 4cdd5f9186bbe80306e76f11da7ecb0b9720433c
>> # good: [13b06b78c772d64e2207e4a5a5329856fe2bf241] Merge branches
>> 'pm-opp', 'pm-misc', 'pm-avs' and 'pm-tools'
>> git bisect good 13b06b78c772d64e2207e4a5a5329856fe2bf241
>> # good: [cf2d213e49fdf47e4c10dc629a3659e0026a54b8] Merge tag 'pm-5.3-
>> rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
>> git bisect good cf2d213e49fdf47e4c10dc629a3659e0026a54b8
>> # bad: [02a93f35f57fe5d4d1bac0ac8496884235e2fd2e] ACPICA: Update
>> version to 20190703 git bisect bad
>> 02a93f35f57fe5d4d1bac0ac8496884235e2fd2e
>> # bad: [d4ca763eed3bcc227f220beb11ff4eb2fa548755] Merge ACPI tables
>> handling changes for v5.3.
>> git bisect bad d4ca763eed3bcc227f220beb11ff4eb2fa548755
>> # bad: [d06c47e3dd07fdf3f07e8fc45f2ce655e9b295c5] ACPI: configfs: Resolve
>> objects on host-directed table loads git bisect bad
>> d06c47e3dd07fdf3f07e8fc45f2ce655e9b295c5
>> # good: [c78fea61f0c1f8568fbbb36ac3d1e1c85a903ae4] ACPI: tables: Allow
>> BGRT to be overridden git bisect good
>> c78fea61f0c1f8568fbbb36ac3d1e1c85a903ae4
>> # first bad commit: [d06c47e3dd07fdf3f07e8fc45f2ce655e9b295c5] ACPI:
>> configfs: Resolve objects on host-directed table loads
>>
>> --
>> With Best Regards,
>> Andy Shevchenko
>>
>
>

Re: [PATCH 1/3] ACPI: Resolve objects on host-directed table loads

[Shevchenko, Andriy]

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?

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 1/3] ACPI: Resolve objects on host-directed table loads

[Nikolaus Voss]

Andy,

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.

Niko

Re: [PATCH 1/3] ACPI: Resolve objects on host-directed table loads

[Shevchenko, Andriy]

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

-- 
With Best Regards,
Andy Shevchenko