Re: "EC: Install address space handler at the namespace root" causing issues for some users

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 8/8/24 7:22 PM, Rafael J. Wysocki wrote:
> Hi,
> 
> On Mon, Aug 5, 2024 at 2:47 PM Hans de Goede <hdegoede@redhat.com> wrote:
>>
>> Hi,
>>
>> On 8/5/24 1:28 PM, Hans de Goede wrote:
>>> Hi,
>>>
>>> On 8/1/24 4:28 PM, Hans de Goede wrote:
>>>> Hi,
>>>>
>>>> On 7/29/24 1:15 PM, Hans de Goede wrote:
>>>>> Hi Rafael,
>>>>>
>>>>> There are 2 bug reports:
>>>>>
>>>>> 1. Brightness up/down key-presses no longer working on LG laptop (acpi-video related):
>>>>> https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/thread/V2KWAGZIAX4TOWPCH6A6FSIT66PR3KMZ/
>>>>
>>>> I have filed:
>>>>
>>>> https://bugzilla.redhat.com/show_bug.cgi?id=2302253
>>>>
>>>> to track this now and an acpidump of the troublesome LG laptop
>>>> is attached there. I have also requested dmesg output of
>>>> a non working kernel to be attached there.
>>>>
>>>> As a reminder this is the bug where it has been confirmed that
>>>> reverting "EC: Install address space handler at the namespace root"
>>>> helps, with the caveat that there is a Thunderbolt related IRQ
>>>> storm on the ACPI event IRQ after the revert ...
>>>
>>> Ok, so the bugzilla now has 2 different dmesg outputs:
>>>
>>> 1. 6.9.6, this kernel works without problems
>>>
>>> 2. 6.9.12 with the following patch you suggested on top:
>>>
>>> --- a/drivers/acpi/ec.c
>>> +++ b/drivers/acpi/ec.c
>>> @@ -1788,7 +1788,7 @@ void __init acpi_ec_dsdt_probe(void)
>>>        * At this point, the GPE is not fully initialized, so do not to
>>>        * handle the events.
>>>        */
>>> -     ret = acpi_ec_setup(ec, NULL, true);
>>> +     ret = acpi_ec_setup(ec, NULL, false);
>>>       if (ret) {
>>>               acpi_ec_free(ec);
>>>               return;
>>>
>>> Unfortunately this does not help. dmesg shows some EC _REG errors, which
>>> are now (with the above diff applied) shown just before the
>>> "Boot DSDT EC initialization complete" message, which shows that _REG now
>>> runs from acpi_ec_add() rather then before:
>>>
>>> [    1.007566] ACPI BIOS Error (bug): Could not resolve symbol [\_TZ.FN00._OFF], AE_NOT_FOUND (20230628/psargs-330)
>>> [    1.007576] ACPI Error: Aborting method \_SB.PC00.LPCB.H_EC.EREG due to previous error (AE_NOT_FOUND) (20230628/psparse-52
>>> [    1.007580] ACPI Error: Aborting method \_SB.PC00.LPCB.H_EC._REG due to previous error (AE_NOT_FOUND) (20230628/psparse-52
>>> [    1.007639] ACPI: EC: interrupt unblocked
>>> [    1.007640] ACPI: EC: event unblocked
>>> [    1.007675] ACPI: EC: EC_CMD/EC_SC=0x66, EC_DATA=0x62
>>> [    1.007676] ACPI: EC: GPE=0x6e
>>> [    1.007677] ACPI: \_SB_.PC00.LPCB.LGEC: Boot DSDT EC initialization complete
>>> [    1.007679] ACPI: \_SB_.PC00.LPCB.LGEC: EC: Used to handle transactions and events
>>>
>>> Note that the errors are from calling _REG on \_SB.PC00.LPCB.H_EC, where as the actual
>>> EC (and the only acpi_device on which _REG would get called for the EC Opregion before) is:
>>> \_SB_.PC00.LPCB.LGEC.
>>>
>>> Looking at the DSDT it seems that the H_EC is not used and is leftover from a copy/paste
>>> from some reference design DSDT. Its _REG however does write to the EC before hitting the error
>>> and I think that that write may be causing the issue...
>>>
>>> The H_EC device does have an _STA method and looking closer the troublesome EREG method is
>>> also called from _INI. So I guess that _STA is returning 0 causing _INI to not run and
>>> that is the reason why we are not seeing the same EREG errors with kernel 6.9.6 where _REG is
>>> only called for the EC opregion on \_SB_.PC00.LPCB.LGEC and not for the entire ACPI device
>>> hierarchy as is done with >= 6.9.7 .
>>>
>>> Maybe we should only call _REG for the EC opregion on present devices (and devices without
>>> a _STA)?
>>>
>>> Also note that both LGEC and H_EC use the same cmd + data ports.
>>>
>>> I'll go and ask the reporter to retrieve the status of both LGEC and H_EC and then see
>>> from there.
>>
>> The reporter has confirmed that of the 2 EC devices ( H_EC / LGEC ) only LGEC returns
>> a _STA of non 0:
>>
>>> Here it is, with kernel 6.9.6:
>>>
>>> $ cat /sys/bus/acpi/devices/PNP0C09\:00/path
>>> \_SB_.PC00.LPCB.H_EC
>>> $ cat /sys/bus/acpi/devices/PNP0C09\:00/status
>>> 0
>>> $ cat /sys/bus/acpi/devices/PNP0C09\:01/path
>>> \_SB_.PC00.LPCB.LGEC
>>> $ cat /sys/bus/acpi/devices/PNP0C09\:01/status
>>> 15
>>
>> And taking a second look at the other bug:
>> https://bugzilla.redhat.com/show_bug.cgi?id=2298938
>>
>> That one also has 2 EC ACPI devices and the errors come from calling _REG on the one
>> which is not picked as the boot_ec :
>>
>> jul 19 17:33:41 kernel: ACPI: EC: EC started
>> jul 19 17:33:41 kernel: ACPI: EC: interrupt blocked
>> jul 19 17:33:41 kernel: ACPI Error: Aborting method \_SB.PCI0.LPCB.H_EC.ECMD due to previous error (AE_AML_LOOP_TIMEOUT) (20230628/psparse-529)
>> jul 19 17:33:41 kernel: ACPI Error: Aborting method \_TZ.FNCL due to previous error (AE_AML_LOOP_TIMEOUT) (20230628/psparse-529)
>> jul 19 17:33:41 kernel: ACPI Error: Aborting method \_TZ.FN00._OFF due to previous error (AE_AML_LOOP_TIMEOUT) (20230628/psparse-529)
>> jul 19 17:33:41 kernel: ACPI Error: Aborting method \_SB.PCI0.LPCB.H_EC._REG due to previous error (AE_AML_LOOP_TIMEOUT) (20230628/psparse-529)
>> jul 19 17:33:41 kernel: ACPI: EC: EC_CMD/EC_SC=0x66, EC_DATA=0x62
>> jul 19 17:33:41 kernel: ACPI: \_SB_.PCI0.LPCB.EC0_: Boot DSDT EC used to handle transactions
>>
>> Note the H_EC vs EC0_ in the errors vs the "Boot DSDT EC used to
>> handle transactions" message.
>>
>> So the issue in both cases seems to be calling _REG on an unused EC acpi_device.
>> Not sure how to best fix this though ...
> 
> I have created an experimental acpi-ec-fixes branch:
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git/log/?h=acpi-ec-fixes
> 
> for this which illustrates my idea (untested so far).

Thank you. I believe that the approach taken here is good and I also
like the code (of the current version) so you may add my:

Reviewed-by: Hans de Goede <hdegoede@redhat.com>

to all 3 patches.

I have started a test Fedora 40 6.10.4 kernel build with the patches from
the acpi-ec-fixes branch added:

https://koji.fedoraproject.org/koji/taskinfo?taskID=121834209

and I have asked the reporters of both bugs:

    2298938 - Multiple ACPI errors resulting in incorrect thermal readings and misleading CPU 
    2302253 - ACPI: EC: LG gram laptop brightness keys stop working with kernel >= 6.9.7

to test this. I expect a good turn around time from the reporter
of bug 2302253. So far the reporter of 2298938 is not really
responsive (holidays?).

Regards,

Hans