diff mbox series

[v3,5/5] arm64: dts: allwinner: a64: Run GPU at 432 MHz

Message ID 20240304-pinephone-pll-fixes-v3-5-94ab828f269a@oltmanns.dev (mailing list archive)
State Not Applicable, archived
Headers show
Series Pinephone video out fixes (flipping between two frames) | expand

Commit Message

Frank Oltmanns March 4, 2024, 7:29 a.m. UTC
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(-)

Comments

Erico Nunes March 6, 2024, 3:04 p.m. UTC | #1
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
diff mbox series

Patch

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>;
 		};