The Allwinner A64's GPU has currently three operating points. However,
the BSP runs the GPU fixed at 432 MHz. In addition, at least one of the
devices using that SoC - the pinephone - shows unstabilities (see link)
that can be circumvented by running the GPU at a fixed rate.

Therefore, remove the other two operating points from the GPU OPP table,
so that the GPU runs at a fixed rate of 432 MHz.

Link: https://gitlab.com/postmarketOS/pmaports/-/issues/805
Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
---
 arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi b/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
index 57ac18738c99..c810380aab6d 100644
--- a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
+++ b/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
@@ -107,14 +107,6 @@ de: display-engine {
 	gpu_opp_table: opp-table-gpu {
 		compatible = "operating-points-v2";
 
-		opp-120000000 {
-			opp-hz = /bits/ 64 <120000000>;
-		};
-
-		opp-312000000 {
-			opp-hz = /bits/ 64 <312000000>;
-		};
-
 		opp-432000000 {
 			opp-hz = /bits/ 64 <432000000>;
 		};

-- 
2.44.0

On Mon, Mar 4, 2024 at 6:01 PM Frank Oltmanns <frank@oltmanns.dev> wrote:
>
> The Allwinner A64's GPU has currently three operating points. However,
> the BSP runs the GPU fixed at 432 MHz. In addition, at least one of the
> devices using that SoC - the pinephone - shows unstabilities (see link)
> that can be circumvented by running the GPU at a fixed rate.
>
> Therefore, remove the other two operating points from the GPU OPP table,
> so that the GPU runs at a fixed rate of 432 MHz.

In addition to all of this, the A64 user manual does say explicitly
that "dynamic frequency scaling is not supported" on PLL_GPU. So I
think this is really needed for a reliable GPU experience on A64.

Acked-by: Erico Nunes <nunes.erico@gmail.com>

Thanks

Erico