On 12/11/2024 2:36 pm, Dragan Simic wrote:
Hello Robin,
On 2024-11-12 15:19, Robin Murphy wrote:
On 10/11/2024 6:44 pm, Dragan Simic wrote:
The regulator-{min,max}-microvolt values for the vdd_gpu regulator in
the
PinePhone Pro device dts file are too restrictive, which prevents the
highest
GPU OPP from being used, slowing the GPU down unnecessarily. Let's
fix that
by making the regulator-{min,max}-microvolt values less strict, using
the
voltage range that the Silergy SYR838 chip used for the vdd_gpu
regulator is
actually capable of producing. [1][2]
Specifying the absolute limits which the regulator driver necessarily
already knows doesn't seem particularly useful... Moreover, the RK3399
datasheet specifies the operating range for GPU_VDD as 0.80-1.20V, so
at the very least, allowing the regulator to go outside that range
seems inadvisable.
Indeed, which is why I already mentioned in the patch description
that I do plan to update the constraints of all regulators to match
the summary of the constraints of their consumers. Though, I plan
to do that later, as a separate directory-wide cleanup, for which
I must find and allocate a substantial amount of time, to make sure
there will be no mistakes.
Sure, but even if every other DT needs fixing, that still doesn't make
it a good idea to deliberately introduce the same mistake to *this* DT
and thus create even more work to fix it again. There's no value in
being consistently wrong over inconsistently wrong - if there's
justification for changing this DT at all, change it to be right.
However there's a separate datasheet for the
RK3399-T variant, which does specify this 875-975mV range and a
maximum GPU clock of 600MHz, along with the same 1.5GHz max.
Cortex-A72 clock as advertised for RK3399S, so it seems quite possible
that these GPU constraints here are in fact intentional as well.
Obviously users are free to overclock and overvolt if they wish - I do
for my actively-cooled RK3399 board :) - but it's a different matter
for mainline to force it upon them.
Well, maybe the RK3399S is the same in that regard as the RK3399-T,
but maybe it actually isn't -- unfortunately, we don't have some
official RK3399S datasheet that would provide us with the required
information. As another, somewhat unrelated example, we don't have
some official documentation to tell us is the RK3399S supposed not
to have working PCI Express interface, which officially isn't present
in the RK3399-T variant.
Looking back at the original submission, v2 *was* proposing the RK3399-T
OPPs, with the GPU capped at 600MHz, and it was said that those are what
PPP *should* be using[1]. It seems there was a semantic objection to
having a separate rk3399-t-opp.dtsi at the time, and when the main DTS
was reworked for v3 the 800MHz GPU OPP seems to have been overlooked.
However, since rk3399-t.dtsi does now exist anyway, it would seem more
logical to just use that instead of including rk3399.dtsi and then
overriding it to be pretty much equivalent to the T variant anyway.
Thanks,
Robin.
[1]
https://lore.kernel.org/linux-rockchip/CAN1fySWVVTeGHAD=_hFH+ZdcR_AEiBc0wqes9Y4VRzB=zcdvSw@xxxxxxxxxxxxxx/
However, I fully agree that forcing any kind of an overclock is not
what we want to do. Thus, I'll do my best, as I already noted in this
thread, to extract the dtb from the "reference" Android build that
Rockchip itself provided for the RK3399S-based PinePhone Pro. That's
closest to the official documentation for the RK3399S variant that we
can get our hands on.
This also eliminates the following error messages from the kernel log:
core: _opp_supported_by_regulators: OPP minuV: 1100000 maxuV:
1150000, not supported by regulator
panfrost ff9a0000.gpu: _opp_add: OPP not supported by regulators
(800000000)
These changes to the regulator-{min,max}-microvolt values make the
PinePhone
Pro device dts consistent with the dts files for other Rockchip
RK3399-based
boards and devices. It's possible to be more strict here, by
specifying the
regulator-{min,max}-microvolt values that don't go outside of what
the GPU
actually may use, as the consumer of the vdd_gpu regulator, but those
changes
are left for a later directory-wide regulator cleanup.
[1]
https://files.pine64.org/doc/PinePhonePro/PinephonePro-Schematic-V1.0-20211127.pdf
[2]
https://www.t-firefly.com/download/Firefly-RK3399/docs/Chip%20Specifications/DC-DC_SYR837_838.pdf
Fixes: 78a21c7d5952 ("arm64: dts: rockchip: Add initial support for
Pine64 PinePhone Pro")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Dragan Simic <dsimic@xxxxxxxxxxx>
---
arch/arm64/boot/dts/rockchip/rk3399-pinephone-pro.dts | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/boot/dts/rockchip/rk3399-pinephone-pro.dts
b/arch/arm64/boot/dts/rockchip/rk3399-pinephone-pro.dts
index 1a44582a49fb..956d64f5b271 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399-pinephone-pro.dts
+++ b/arch/arm64/boot/dts/rockchip/rk3399-pinephone-pro.dts
@@ -410,8 +410,8 @@ vdd_gpu: regulator@41 {
pinctrl-names = "default";
pinctrl-0 = <&vsel2_pin>;
regulator-name = "vdd_gpu";
- regulator-min-microvolt = <875000>;
- regulator-max-microvolt = <975000>;
+ regulator-min-microvolt = <712500>;
+ regulator-max-microvolt = <1500000>;
regulator-ramp-delay = <1000>;
regulator-always-on;
regulator-boot-on;
