Re: [PATCH] arm64: dts: qcom: sc8280xp-huawei-gaokun3: Add dsi panel DT node

[Pengyu Luo]

On Wed, Jul 1, 2026 at 7:45 PM Konrad Dybcio
<konrad.dybcio@xxxxxxxxxxxxxxxx> wrote:
>
> On 6/30/26 12:41 PM, Pengyu Luo wrote:
> > On Tue, Jun 30, 2026 at 6:34 PM Konrad Dybcio
> > <konrad.dybcio@xxxxxxxxxxxxxxxx> wrote:
> >>
> >> On 6/30/26 12:30 PM, Pengyu Luo wrote:
> >>> On Tue, Jun 30, 2026 at 6:29 PM Konrad Dybcio
> >>> <konrad.dybcio@xxxxxxxxxxxxxxxx> wrote:
> >>>>
> >>>> On 6/30/26 11:28 AM, Pengyu Luo wrote:
> >>>>> On Tue, Jun 30, 2026 at 5:18 PM Konrad Dybcio
> >>>>> <konrad.dybcio@xxxxxxxxxxxxxxxx> wrote:
> >>>>>>
> >>>>>> On 6/30/26 6:22 AM, Pengyu Luo wrote:
> >>>>>>> DSI panel driver have been added for a while, so add the DT node to
> >>>>>>> enable it. vdd{a,s}-supply for dsi, dsi_phy are blank since the DSDT
> >>>>>>> describes the wrong, no impact after manual disabling these wrong
> >>>>>>> supplies.
> >>>>>>>
> >>>>>>> Signed-off-by: Pengyu Luo <mitltlatltl@xxxxxxxxx>
> >>>>>>> ---
> >>>>>>
> >>>>>> [...]
> >>>>>>
> >>>>>>> +&mdss0_dsi0 {
> >>>>>>> +     /* real vdda is unknown */
> >>>>>>> +
> >>>>>>
> >>>>>> L3B: DSI core 1.2 V (both?)
> >>>>>> L6B: DSI0/1 PLL and core 0.9 V
> >>>>>>
> >>>>>
> >>>>> Yes, that is what I saw in the DSDT, however, I can disable them
> >>>>> safely (hack the regulator driver to add a sysfs to handle these
> >>>>> regulators), the panel works well.
> >>>>
> >>>> L3B additionally powers CSIPHY2/3, EDP0/1, REFGEN (probably why it
> >>>> ends up being on), UFSPHY and USB1_PHY
> >>>>
> >>>> L6B additionally powers the same components, minus refgen and USB
> >>>>
> >>>
> >>> No, I confirmed they are totally disabled, since there is a way to check it now.
> >>> https://lore.kernel.org/linux-arm-msm/20260420-read-rpmh-v3-v4-0-70c152e6c958@xxxxxxxxxxxxxxxx/
> >>
> >> This presents you with the status of the votes casted by HLOS, not
> >> the actual hardware state
> >>
> >
> > If so, non-HLOS will vote on some critical regulators to keep them on,
> > IIRC, once I disabled L9D, system reseted immediately.
>
> NHLOS will generally ensure that the hardware that it needs is
> powered. This does not extend to hardware that *you* may want to
> access in Linux (or which was left online by UEFI), which I suspect
> was the case here
>
> >> To get the latter, you'd have to dump the SPMI registers
> >>
> > I will appreciate it if you provide more information.
>
> Take a look at drivers/regulator/qcom_spmi-regulator.c, you can get
> the actual live value of the enable register and the voltage selector
> for each regulator
>

Thanks! I will look into this later.

Best wishes,
Pengyu

> Konrad