On some pinephones the video output sometimes freezes (flips between two frames) [1]. It seems to be that the reason for this behaviour is that PLL-MIPI is outside its limits, and the GPU is not running at a fixed rate.
In this patch series I propose the following changes: 1. sunxi-ng: Adhere to the following constraints given in the Allwinner A64 Manual regarding PLL-MIPI: * M/N <= 3 * (PLL_VIDEO0)/M >= 24MHz * 500MHz <= clockrate <= 1400MHz
2. Remove two operating points from the A64 DTS OPPs, so that the GPU runs at a fixed rate of 432 MHz.
Note, that when pinning the GPU to 432 MHz the issue [1] completely disappears for me. I've searched the BSP and could not find any indication that supports the idea of having the three OPPs. The only frequency I found in the BPSs for A64 is 432 MHz, which has also proven stable for me.
I very much appreciate your feedback!
[1] https://gitlab.com/postmarketOS/pmaports/-/issues/805
Signed-off-by: Frank Oltmanns frank@oltmanns.dev --- Changes in v4: - sunxi-ng: common: Address review comments. - Link to v3: https://lore.kernel.org/r/20240304-pinephone-pll-fixes-v3-0-94ab828f269a@olt...
Changes in v3: - dts: Pin GPU to 432 MHz. - nkm and a64: Move minimum and maximum rate handling to the common part of the sunxi-ng driver. - Removed st7703 patch from series. - Link to v2: https://lore.kernel.org/r/20240205-pinephone-pll-fixes-v2-0-96a46a2d8c9b@olt...
Changes in v2: - dts: Increase minimum GPU frequency to 192 MHz. - nkm and a64: Add minimum and maximum rate for PLL-MIPI. - nkm: Use the same approach for skipping invalid rates in ccu_nkm_find_best() as in ccu_nkm_find_best_with_parent_adj(). - nkm: Improve names for ratio struct members and hence get rid of describing comments. - nkm and a64: Correct description in the commit messages: M/N <= 3 - Remove patches for nm as they were not needed. - st7703: Rework the commit message to cover more background for the change. - Link to v1: https://lore.kernel.org/r/20231218-pinephone-pll-fixes-v1-0-e238b6ed6dc1@olt...
--- Frank Oltmanns (5): clk: sunxi-ng: common: Support minimum and maximum rate clk: sunxi-ng: a64: Set minimum and maximum rate for PLL-MIPI clk: sunxi-ng: nkm: Support constraints on m/n ratio and parent rate clk: sunxi-ng: a64: Add constraints on PLL-MIPI's n/m ratio and parent rate arm64: dts: allwinner: a64: Run GPU at 432 MHz
arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi | 8 -------- drivers/clk/sunxi-ng/ccu-sun50i-a64.c | 14 +++++++++----- drivers/clk/sunxi-ng/ccu_common.c | 19 +++++++++++++++++++ drivers/clk/sunxi-ng/ccu_common.h | 3 +++ drivers/clk/sunxi-ng/ccu_nkm.c | 21 +++++++++++++++++++++ drivers/clk/sunxi-ng/ccu_nkm.h | 2 ++ 6 files changed, 54 insertions(+), 13 deletions(-) --- base-commit: dcb6c8ee6acc6c347caec1e73fb900c0f4ff9806 change-id: 20231218-pinephone-pll-fixes-0ccdfde273e4
Best regards,