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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Proofpoint-GUID: ys5KfQpfcoS491PteTLKZhLUPimHAXCL X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTA1MDA3MyBTYWx0ZWRfX7eXxTjp/gxwM DBJzvbhrME17y5RNmsK0eb6VX0wcDFqhB/0zeV/JbGGql0I8zzxAV+EbZsn+QstrXYDJ8jWFuIf azuYhtq452sOTWhv1qWSpamesETP6nK/hjKScHiKzFz41/miB281y7Okt5jOtmDIVpgg1HYOJHe b2D2pcdn2qbWGMpy6Qch17rcV1SfIsw0KkrxsAOviG7xvrCNdnqrm/vSn4Fa1bGFv/h88pf3KIJ IIKlBVfnXDsUfAGaroXawhli09Yrk6Q3QwRx8UO6O6+EZeJX6lO83exz149vbPHi5cDjVMMbb2Z Pa6GczSpkRmBj9cSYurEcSMrIxP9F8A8hEZY3Sj2EaoDNvtgsyIjo7wlhefF5ScCLt2HsA+FQB8 zRGV6Tgbe4ifhgj+1oeRjm8qWwCksA== X-Authority-Analysis: v=2.4 cv=OayVzxTY c=1 sm=1 tr=0 ts=690b1fcb cx=c_pps a=hnmNkyzTK/kJ09Xio7VxxA==:117 a=Uz3yg00KUFJ2y2WijEJ4bw==:17 a=IkcTkHD0fZMA:10 a=6UeiqGixMTsA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VwQbUJbxAAAA:8 a=KKAkSRfTAAAA:8 a=EUspDBNiAAAA:8 a=hMESfBkPYkNm0GZuxn0A:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 a=PEH46H7Ffwr30OY-TuGO:22 a=cvBusfyB2V15izCimMoJ:22 X-Proofpoint-ORIG-GUID: ys5KfQpfcoS491PteTLKZhLUPimHAXCL X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-11-05_04,2025-11-03_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 clxscore=1015 phishscore=0 adultscore=0 impostorscore=0 bulkscore=0 suspectscore=0 spamscore=0 lowpriorityscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2510240001 definitions=main-2511050073 On 10/30/2025 7:27 PM, Konrad Dybcio wrote: > On 10/30/25 12:07 PM, Yongxing Mou wrote: >> >> >> On 10/30/2025 5:41 PM, Konrad Dybcio wrote: >>> On 10/30/25 10:08 AM, Yongxing Mou wrote: >>>> >>>> >>>> On 10/28/2025 5:08 PM, Konrad Dybcio wrote: >>>>> On 10/28/25 8:04 AM, Yongxing Mou wrote: >>>>>> Previously, the eDP panel backlight was enabled via UEFI. Added backlight >>>>>> control node in kernel DTS due to some meta may not enable the backlight. >>>>>> >>>>>> Aligned with other x1e80100-based platforms: the PWM signal is controlled >>>>>> by PMK8550, and the backlight enable signal is handled by PMC8380. >>>>>> >>>>>> Signed-off-by: Yongxing Mou >>>>>> --- >>>>> >>>>> The subject must say "hamoa-iot-evk:" >>>> Thanks and got it , will fix it in next version.>> arch/arm64/boot/dts/qcom/hamoa-iot-evk.dts | 55 ++++++++++++++++++++++++++++++ >>>>>>    1 file changed, 55 insertions(+) >>>>>> >>>>>> diff --git a/arch/arm64/boot/dts/qcom/hamoa-iot-evk.dts b/arch/arm64/boot/dts/qcom/hamoa-iot-evk.dts >>>>>> index 36dd6599402b4650b7f8ad2c0cd22212116a25fe..fda1b3a3c7673be74832c27849231cba4bc1f25f 100644 >>>>>> --- a/arch/arm64/boot/dts/qcom/hamoa-iot-evk.dts >>>>>> +++ b/arch/arm64/boot/dts/qcom/hamoa-iot-evk.dts >>>>>> @@ -17,6 +17,16 @@ aliases { >>>>>>            serial1 = &uart14; >>>>>>        }; >>>>>>    +    backlight: backlight { >>>>>> +        compatible = "pwm-backlight"; >>>>>> +        pwms = <&pmk8550_pwm 0 5000000>; >>>>> >>>>> Try adjusting the backlight value.. you'll find some funny behavior >>>>> near the max level.. which reminds me I should send some fixes for >>>>> some laptop DTs >>>>> >>>>   I tried sliding the backlight between the maximum and minimum values. It seems that at a certain sliding speed, when approaching the maximum value, there is some brightness flickering. Is this the phenomenon you’re referring to?> [...] >>> >>> "maybe" - for me it was the brightness actually going down beyond ~80% >>> >>> The issue is that the PWM hardware can't really do a period that's >>> == 5000000 ns >>> >>> But it seems like this is no longer an issue since the driver now >>> rounds up to the closest supported value, see last couple commits >>> to drivers/leds/rgb/leds-qcom-lpg.c >>> >>> Konrad >> Oh,thanks for sharing that. I saw the phenomenon you mentioned. Previously, my baseline had already merged this patch series: https://lore.kernel.org/all/20250305-leds-qcom-lpg-fix-max-pwm-on-hi-res-v4-0-bfe124a53a9f@linaro.org/, so I didn’t observe the ‘brightness actually going down beyond ~80%.’and just very slight flickering. After I reverted patches, it indeed appeared.  So here i want to confirm, >> pwms = <&pmk8550_pwm 0 5000000> >> can i keep the value 5000000 ? > > I think so.. perhaps make sure the period is appropriate for > the backlight device at the other end since you mentioned it's > flickering > > Konrad Compared to ‘brightness actually going down beyond ~80%’, this is just a very slight flicker that only occurs when sliding the brightness bar at a specific speed.It won’t occur in most cases. Also tried another value pwms = <&pmk8550_pwm 0 4266537>, and it looks the same, so can we keep it at 5000000 here?