* [PATCH v3] ACPI: video: Put ACPI video and its child devices to D0 at boot
@ 2023-07-21 15:21 Kai-Heng Feng
2023-07-21 15:45 ` Rafael J. Wysocki
0 siblings, 1 reply; 4+ messages in thread
From: Kai-Heng Feng @ 2023-07-21 15:21 UTC (permalink / raw)
To: rafael, lenb, hdegoede; +Cc: Kai-Heng Feng, linux-acpi, linux-kernel
Screen brightness can only be changed once on HP ZBook Fury 16 G10.
Vendor identified the root cause as Linux doesn't invoke _PS0 at boot
for all ACPI devices:
Scope (\_SB.PC00.GFX0)
{
Scope (DD1F)
{
Method (_PS0, 0, Serialized) // _PS0: Power State 0
{
If (CondRefOf (\_SB.PC00.LPCB.EC0.SSBC))
{
\_SB.PC00.LPCB.EC0.SSBC ()
}
}
...
}
...
}
The \_SB.PC00.GFX0.DD1F is the panel device, and its _PS0 needs to be
executed to make the brightness control work properly.
_PS0 doesn't get invoked for this device because _PSC is missing,
which violates ACPI spec 6.3, section 7.3.6. Commit 7cd8407d53ef
("ACPI / PM: Do not execute _PS0 for devices without _PSC during
initialization") tried to workaround missing _PSC on defective
firmwares, but got reverted because of regression.
So the safest approach is to use acpi_device_fix_up_power_extended() to
put ACPI video and its child devices to D0 to workaround the issue.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217683
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
v3:
- Wording change to make it clear it's a firmware issue.
- Specify the device name in comment.
v2:
- Wording
- Bugzilla
- Add comment
drivers/acpi/acpi_video.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c
index 62f4364e4460..1732780a672b 100644
--- a/drivers/acpi/acpi_video.c
+++ b/drivers/acpi/acpi_video.c
@@ -2027,6 +2027,12 @@ static int acpi_video_bus_add(struct acpi_device *device)
if (error)
goto err_put_video;
+ /*
+ * HP ZBook Fury 16 G10 requires ACPI video's child devices have _PS0
+ * evaluated to have functional panel brightness control.
+ */
+ acpi_device_fix_up_power_extended(device);
+
pr_info("%s [%s] (multi-head: %s rom: %s post: %s)\n",
ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
video->flags.multihead ? "yes" : "no",
--
2.34.1
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v3] ACPI: video: Put ACPI video and its child devices to D0 at boot
2023-07-21 15:21 [PATCH v3] ACPI: video: Put ACPI video and its child devices to D0 at boot Kai-Heng Feng
@ 2023-07-21 15:45 ` Rafael J. Wysocki
2023-07-25 8:39 ` Hans de Goede
0 siblings, 1 reply; 4+ messages in thread
From: Rafael J. Wysocki @ 2023-07-21 15:45 UTC (permalink / raw)
To: Kai-Heng Feng, hdegoede; +Cc: rafael, lenb, linux-acpi, linux-kernel
Thanks for the update!
On Fri, Jul 21, 2023 at 5:22 PM Kai-Heng Feng
<kai.heng.feng@canonical.com> wrote:
>
> Screen brightness can only be changed once on HP ZBook Fury 16 G10.
>
> Vendor identified the root cause as Linux doesn't invoke _PS0 at boot
> for all ACPI devices:
>
> Scope (\_SB.PC00.GFX0)
> {
> Scope (DD1F)
> {
> Method (_PS0, 0, Serialized) // _PS0: Power State 0
> {
> If (CondRefOf (\_SB.PC00.LPCB.EC0.SSBC))
> {
> \_SB.PC00.LPCB.EC0.SSBC ()
> }
> }
> ...
> }
> ...
> }
>
> The \_SB.PC00.GFX0.DD1F is the panel device, and its _PS0 needs to be
> executed to make the brightness control work properly.
>
> _PS0 doesn't get invoked for this device because _PSC is missing,
> which violates ACPI spec 6.3, section 7.3.6. Commit 7cd8407d53ef
> ("ACPI / PM: Do not execute _PS0 for devices without _PSC during
> initialization") tried to workaround missing _PSC on defective
> firmwares, but got reverted because of regression.
>
> So the safest approach is to use acpi_device_fix_up_power_extended() to
> put ACPI video and its child devices to D0 to workaround the issue.
>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=217683
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Hans, what do you think?
> ---
> v3:
> - Wording change to make it clear it's a firmware issue.
> - Specify the device name in comment.
>
> v2:
> - Wording
> - Bugzilla
> - Add comment
>
> drivers/acpi/acpi_video.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c
> index 62f4364e4460..1732780a672b 100644
> --- a/drivers/acpi/acpi_video.c
> +++ b/drivers/acpi/acpi_video.c
> @@ -2027,6 +2027,12 @@ static int acpi_video_bus_add(struct acpi_device *device)
> if (error)
> goto err_put_video;
>
> + /*
> + * HP ZBook Fury 16 G10 requires ACPI video's child devices have _PS0
> + * evaluated to have functional panel brightness control.
> + */
> + acpi_device_fix_up_power_extended(device);
> +
> pr_info("%s [%s] (multi-head: %s rom: %s post: %s)\n",
> ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
> video->flags.multihead ? "yes" : "no",
> --
> 2.34.1
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v3] ACPI: video: Put ACPI video and its child devices to D0 at boot
2023-07-21 15:45 ` Rafael J. Wysocki
@ 2023-07-25 8:39 ` Hans de Goede
2023-08-17 17:25 ` Rafael J. Wysocki
0 siblings, 1 reply; 4+ messages in thread
From: Hans de Goede @ 2023-07-25 8:39 UTC (permalink / raw)
To: Rafael J. Wysocki, Kai-Heng Feng; +Cc: lenb, linux-acpi, linux-kernel
Hi,
On 7/21/23 17:45, Rafael J. Wysocki wrote:
> Thanks for the update!
>
> On Fri, Jul 21, 2023 at 5:22 PM Kai-Heng Feng
> <kai.heng.feng@canonical.com> wrote:
>>
>> Screen brightness can only be changed once on HP ZBook Fury 16 G10.
>>
>> Vendor identified the root cause as Linux doesn't invoke _PS0 at boot
>> for all ACPI devices:
>>
>> Scope (\_SB.PC00.GFX0)
>> {
>> Scope (DD1F)
>> {
>> Method (_PS0, 0, Serialized) // _PS0: Power State 0
>> {
>> If (CondRefOf (\_SB.PC00.LPCB.EC0.SSBC))
>> {
>> \_SB.PC00.LPCB.EC0.SSBC ()
>> }
>> }
>> ...
>> }
>> ...
>> }
>>
>> The \_SB.PC00.GFX0.DD1F is the panel device, and its _PS0 needs to be
>> executed to make the brightness control work properly.
>>
>> _PS0 doesn't get invoked for this device because _PSC is missing,
>> which violates ACPI spec 6.3, section 7.3.6. Commit 7cd8407d53ef
>> ("ACPI / PM: Do not execute _PS0 for devices without _PSC during
>> initialization") tried to workaround missing _PSC on defective
>> firmwares, but got reverted because of regression.
>>
>> So the safest approach is to use acpi_device_fix_up_power_extended() to
>> put ACPI video and its child devices to D0 to workaround the issue.
>>
>> Link: https://bugzilla.kernel.org/show_bug.cgi?id=217683
>> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
>
> Hans, what do you think?
I believe most (almost all?) child devices of the GFX0 (and other
acpi-video) ACPI device will not have a _PS0. So wrt child-devices
this should mostly be a no-op.
However the GFX0 ACPI device is the ACPI companion for the PCI
device for the GPU, so this will also execute _PS0 on the GPU,
we do that every suspend/resume cycle so this should be fine.
But if we do see regressions then we may need to rework this
to skip the _PS0 on the GPU itself.
With that caveat this looks good to me:
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Regards,
Hans
>
>> ---
>> v3:
>> - Wording change to make it clear it's a firmware issue.
>> - Specify the device name in comment.
>>
>> v2:
>> - Wording
>> - Bugzilla
>> - Add comment
>>
>> drivers/acpi/acpi_video.c | 6 ++++++
>> 1 file changed, 6 insertions(+)
>>
>> diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c
>> index 62f4364e4460..1732780a672b 100644
>> --- a/drivers/acpi/acpi_video.c
>> +++ b/drivers/acpi/acpi_video.c
>> @@ -2027,6 +2027,12 @@ static int acpi_video_bus_add(struct acpi_device *device)
>> if (error)
>> goto err_put_video;
>>
>> + /*
>> + * HP ZBook Fury 16 G10 requires ACPI video's child devices have _PS0
>> + * evaluated to have functional panel brightness control.
>> + */
>> + acpi_device_fix_up_power_extended(device);
>> +
>> pr_info("%s [%s] (multi-head: %s rom: %s post: %s)\n",
>> ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
>> video->flags.multihead ? "yes" : "no",
>> --
>> 2.34.1
>>
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v3] ACPI: video: Put ACPI video and its child devices to D0 at boot
2023-07-25 8:39 ` Hans de Goede
@ 2023-08-17 17:25 ` Rafael J. Wysocki
0 siblings, 0 replies; 4+ messages in thread
From: Rafael J. Wysocki @ 2023-08-17 17:25 UTC (permalink / raw)
To: Hans de Goede, Kai-Heng Feng; +Cc: linux-acpi, linux-kernel
On Tue, Jul 25, 2023 at 10:39 AM Hans de Goede <hdegoede@redhat.com> wrote:
>
> Hi,
>
> On 7/21/23 17:45, Rafael J. Wysocki wrote:
> > Thanks for the update!
> >
> > On Fri, Jul 21, 2023 at 5:22 PM Kai-Heng Feng
> > <kai.heng.feng@canonical.com> wrote:
> >>
> >> Screen brightness can only be changed once on HP ZBook Fury 16 G10.
> >>
> >> Vendor identified the root cause as Linux doesn't invoke _PS0 at boot
> >> for all ACPI devices:
> >>
> >> Scope (\_SB.PC00.GFX0)
> >> {
> >> Scope (DD1F)
> >> {
> >> Method (_PS0, 0, Serialized) // _PS0: Power State 0
> >> {
> >> If (CondRefOf (\_SB.PC00.LPCB.EC0.SSBC))
> >> {
> >> \_SB.PC00.LPCB.EC0.SSBC ()
> >> }
> >> }
> >> ...
> >> }
> >> ...
> >> }
> >>
> >> The \_SB.PC00.GFX0.DD1F is the panel device, and its _PS0 needs to be
> >> executed to make the brightness control work properly.
> >>
> >> _PS0 doesn't get invoked for this device because _PSC is missing,
> >> which violates ACPI spec 6.3, section 7.3.6. Commit 7cd8407d53ef
> >> ("ACPI / PM: Do not execute _PS0 for devices without _PSC during
> >> initialization") tried to workaround missing _PSC on defective
> >> firmwares, but got reverted because of regression.
> >>
> >> So the safest approach is to use acpi_device_fix_up_power_extended() to
> >> put ACPI video and its child devices to D0 to workaround the issue.
> >>
> >> Link: https://bugzilla.kernel.org/show_bug.cgi?id=217683
> >> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> >
> > Hans, what do you think?
>
> I believe most (almost all?) child devices of the GFX0 (and other
> acpi-video) ACPI device will not have a _PS0. So wrt child-devices
> this should mostly be a no-op.
>
> However the GFX0 ACPI device is the ACPI companion for the PCI
> device for the GPU, so this will also execute _PS0 on the GPU,
> we do that every suspend/resume cycle so this should be fine.
>
> But if we do see regressions then we may need to rework this
> to skip the _PS0 on the GPU itself.
>
> With that caveat this looks good to me:
>
> Reviewed-by: Hans de Goede <hdegoede@redhat.com>
So I've edited the subject (slightly) and the changelog of this patch
and applied it as 6.6 material, thanks!
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2023-08-17 17:26 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-07-21 15:21 [PATCH v3] ACPI: video: Put ACPI video and its child devices to D0 at boot Kai-Heng Feng
2023-07-21 15:45 ` Rafael J. Wysocki
2023-07-25 8:39 ` Hans de Goede
2023-08-17 17:25 ` Rafael J. Wysocki
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