Re: [PATCH 5.16 regression fix 0/5] ACPI: scan: Skip turning off some unused objects during scan

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

Hi,

On 11/18/21 15:51, Rafael J. Wysocki wrote:
> On Thursday, November 18, 2021 12:15:28 PM CET Hans de Goede wrote:
>> Hi,
>>
>> On 11/18/21 12:08, Rafael J. Wysocki wrote:
>>> On Wed, Nov 17, 2021 at 11:01 PM Hans de Goede <hdegoede@redhat.com> wrote:
>>>>
>>>> Hi Rafael,
>>>>
>>>> Commit c10383e8ddf4 ("ACPI: scan: Release PM resources blocked by
>>>> unused objects") adds a:
>>>>
>>>>         bus_for_each_dev(&acpi_bus_type, NULL, NULL, acpi_dev_turn_off_if_unused);
>>>>
>>>> call to acpi_scan_init(). On some devices with buggy DSDTs calling
>>>> _PS3 for one device may result in it turning off another device.
>>>
>>> Well, I'm going to revert this commit.  I'm sending a pull request
>>> with the revert later today.
>>>
>>>> Specifically the DSDT of the GPD win and GPD pocket devices has a
>>>> "\\_SB_.PCI0.SDHB.BRC1" device for a non existing SDIO wifi module
>>>> which _PS3 method sets a GPIO causing the PCI wifi card to turn off.
>>>>
>>>> I've an earlier, in some ways simpler, fix for this here:
>>>> https://fedorapeople.org/~jwrdegoede/0001-ACPI-scan-Skip-turning-off-some-unused-objects-durin.patch
>>>>
>>>> But the sdhci-acpi.c MMC host code already has an older workaround
>>>> for it to not toggle power on this broken ACPI object; and this
>>>> simpler fix would require keeping that workaround. So then we would
>>>> have 2 workarounds for the same issue in the kernel.
>>>>
>>>> Thus instead I've come up with a slightly different approach which
>>>> IMHO has ended up pretty well.
>>>>
>>>> Patches 1-3 of this series are this different approach and assuming
>>>> they are considered ok must be merged into 5.16 to fix the regression
>>>> caused by commit c10383e8ddf4 on these devices.
>>>
>>> So I'll have a look at these and if they look good, we can do that
>>> instead of the problematic commit in 5.17.
>>
>> I'm a bit confused now, if the problematic commit is going to get
>> reversed then technically we don't need this series anymore ?
> 
> That's correct.
> 
>> Or are you planning on re-introducing it in some form for 5.17 ?
> 
> I have been considering this.
> 
>> With that said getting this series merged would still be good,
>> patch 1 + 2 make the existing always_present quirk code more generic
>> which might be useful later. And then patch 3 (which is small)
>> allows dropping some ugliness from the sdhci-acpi.c code since
>> the DSDT bug we are hitting will now be solved by the
>> new acpi-dev-status-override mechanism.
> 
> OK, so this would be applicable for 5.17, but a couple of changelogs
> need to be updated if I'm not mistaken.
> 
> Can you please do that and resend the series?

I will update some of the commit messages and send a v2 tomorrow.

Regards,

Hans