arm64: dts: qcom: sdm845-tama: Keep labibb on, so kernel can disable it

[PATCH] arm64: dts: qcom: sdm845-tama: Keep labibb on, so kernel can disable it

Posted by David Heidelberg via B4 Relay 2 months, 1 week ago

From: David Heidelberg <david@ixit.cz>

In case if they were enabled by the bootloader as part of some
reference/common routine and left hanging. Linux will switch them off if
they're never used.

Discussion about it can be found here:
  https://lore.kernel.org/all/20251130-oneplus-labibb-v1-1-bb3653e43120@ixit.cz/

Fixes: 5dcc6587fde2 ("arm64: dts: qcom: sdm845-tama: Add display nodes")
Suggested-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: David Heidelberg <david@ixit.cz>
---
 arch/arm64/boot/dts/qcom/sdm845-sony-xperia-tama-akatsuki.dts | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/sdm845-sony-xperia-tama-akatsuki.dts b/arch/arm64/boot/dts/qcom/sdm845-sony-xperia-tama-akatsuki.dts
index 82e59e4533549..c2b38ecb2e9cf 100644
--- a/arch/arm64/boot/dts/qcom/sdm845-sony-xperia-tama-akatsuki.dts
+++ b/arch/arm64/boot/dts/qcom/sdm845-sony-xperia-tama-akatsuki.dts
@@ -28,14 +28,6 @@ ts_vddio_supply: ts-vddio-regulator {
 	};
 };
 
-&ibb {
-	status = "disabled";
-};
-
-&lab {
-	status = "disabled";
-};
-
 &panel {
 	/* Akatsuki uses an OLED panel. */
 	/delete-property/ backlight;

---
base-commit: 95cb2fd6ce0ad61af54191fe5ef271d7177f9c3a
change-id: 20251202-tama-labibb-352d0e3b535a

Best regards,
-- 
David Heidelberg <david@ixit.cz>

Re: [PATCH] arm64: dts: qcom: sdm845-tama: Keep labibb on, so kernel can disable it

Posted by Bjorn Andersson 1 month ago

On Tue, Dec 02, 2025 at 12:31:11PM +0100, David Heidelberg via B4 Relay wrote:
> From: David Heidelberg <david@ixit.cz>
> 
> In case if they were enabled by the bootloader as part of some
> reference/common routine and left hanging. Linux will switch them off if
> they're never used.

"""
It's observed that the bootloader on this device will enable the labibb
and leave them enabled, despite being unsed as these devices come with
OLED screens.

Leave the nodes active in DeviceTree to allow the operating system to
turn them off.
"""

> 
> Discussion about it can be found here:
>   https://lore.kernel.org/all/20251130-oneplus-labibb-v1-1-bb3653e43120@ixit.cz/

I think above captures the discussion, so the link can be omitted?

Regards,
Bjorn

> 
> Fixes: 5dcc6587fde2 ("arm64: dts: qcom: sdm845-tama: Add display nodes")
> Suggested-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
> Signed-off-by: David Heidelberg <david@ixit.cz>
> ---
>  arch/arm64/boot/dts/qcom/sdm845-sony-xperia-tama-akatsuki.dts | 8 --------
>  1 file changed, 8 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/qcom/sdm845-sony-xperia-tama-akatsuki.dts b/arch/arm64/boot/dts/qcom/sdm845-sony-xperia-tama-akatsuki.dts
> index 82e59e4533549..c2b38ecb2e9cf 100644
> --- a/arch/arm64/boot/dts/qcom/sdm845-sony-xperia-tama-akatsuki.dts
> +++ b/arch/arm64/boot/dts/qcom/sdm845-sony-xperia-tama-akatsuki.dts
> @@ -28,14 +28,6 @@ ts_vddio_supply: ts-vddio-regulator {
>  	};
>  };
>  
> -&ibb {
> -	status = "disabled";
> -};
> -
> -&lab {
> -	status = "disabled";
> -};
> -
>  &panel {
>  	/* Akatsuki uses an OLED panel. */
>  	/delete-property/ backlight;
> 
> ---
> base-commit: 95cb2fd6ce0ad61af54191fe5ef271d7177f9c3a
> change-id: 20251202-tama-labibb-352d0e3b535a
> 
> Best regards,
> -- 
> David Heidelberg <david@ixit.cz>
> 
>

Re: [PATCH] arm64: dts: qcom: sdm845-tama: Keep labibb on, so kernel can disable it

Posted by Konrad Dybcio 2 months, 1 week ago

On 12/2/25 12:31 PM, David Heidelberg via B4 Relay wrote:
> From: David Heidelberg <david@ixit.cz>
> 
> In case if they were enabled by the bootloader as part of some
> reference/common routine and left hanging. Linux will switch them off if
> they're never used.
> 
> Discussion about it can be found here:
>   https://lore.kernel.org/all/20251130-oneplus-labibb-v1-1-bb3653e43120@ixit.cz/
> 
> Fixes: 5dcc6587fde2 ("arm64: dts: qcom: sdm845-tama: Add display nodes")
> Suggested-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
> Signed-off-by: David Heidelberg <david@ixit.cz>
> ---

Perhaps "keeping it on" is a little bit unfortunate in that the wording
collides with keeping the regulator's output enabled, but anyway

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

Konrad

Re: [PATCH] arm64: dts: qcom: sdm845-tama: Keep labibb on, so kernel can disable it

Posted by David Heidelberg 1 month, 3 weeks ago

On 02/12/2025 13:55, Konrad Dybcio wrote:
> On 12/2/25 12:31 PM, David Heidelberg via B4 Relay wrote:
>> From: David Heidelberg <david@ixit.cz>
>>
>> In case if they were enabled by the bootloader as part of some
>> reference/common routine and left hanging. Linux will switch them off if
>> they're never used.
>>
>> Discussion about it can be found here:
>>    https://lore.kernel.org/all/20251130-oneplus-labibb-v1-1-bb3653e43120@ixit.cz/
>>
>> Fixes: 5dcc6587fde2 ("arm64: dts: qcom: sdm845-tama: Add display nodes")
>> Suggested-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
>> Signed-off-by: David Heidelberg <david@ixit.cz>
>> ---
> 
> Perhaps "keeping it on" is a little bit unfortunate in that the wording
> collides with keeping the regulator's output enabled, but anyway
> 
> Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

So, friend fixed tama-akatsuki against -next tree and having labibb 
nodes there crashes the kernel, so it seems disabling labibb had some 
reason.

So, please do not merge until figured out!

David

> 
> Konrad

-- 
David Heidelberg

Re: [PATCH] arm64: dts: qcom: sdm845-tama: Keep labibb on, so kernel can disable it

Posted by Konrad Dybcio 1 month, 1 week ago

On 12/15/25 8:07 PM, David Heidelberg wrote:
> On 02/12/2025 13:55, Konrad Dybcio wrote:
>> On 12/2/25 12:31 PM, David Heidelberg via B4 Relay wrote:
>>> From: David Heidelberg <david@ixit.cz>
>>>
>>> In case if they were enabled by the bootloader as part of some
>>> reference/common routine and left hanging. Linux will switch them off if
>>> they're never used.
>>>
>>> Discussion about it can be found here:
>>>    https://lore.kernel.org/all/20251130-oneplus-labibb-v1-1-bb3653e43120@ixit.cz/
>>>
>>> Fixes: 5dcc6587fde2 ("arm64: dts: qcom: sdm845-tama: Add display nodes")
>>> Suggested-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
>>> Signed-off-by: David Heidelberg <david@ixit.cz>
>>> ---
>>
>> Perhaps "keeping it on" is a little bit unfortunate in that the wording
>> collides with keeping the regulator's output enabled, but anyway
>>
>> Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
> 
> So, friend fixed tama-akatsuki against -next tree and having labibb nodes there crashes the kernel, so it seems disabling labibb had some reason.
> 
> So, please do not merge until figured out!

+Marijn could you take a look?

Konrad

Re: [PATCH] arm64: dts: qcom: sdm845-tama: Keep labibb on, so kernel can disable it

Posted by David Heidelberg 2 months, 1 week ago

On 02/12/2025 13:55, Konrad Dybcio wrote:
[...]
> 
> Perhaps "keeping it on" is a little bit unfortunate in that the wording
> collides with keeping the regulator's output enabled, but anyway

Yeah, I still can't figure better wording... :(

Anyway, I'm still thinking about the driver. We disable &lab and &ibb 
node, but the parent &labibb node should be loaded. Thus - in the theory 
- driver, should operate.

I don't think it's extra important, but it sounds this should be the 
right way.

David


> 
> Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
> 
> Konrad

-- 
David Heidelberg