[Letux-kernel] BOG: commit 89c7cb1608ac3 ("of/device: Update dma_range_map only when dev has valid dma-ranges") seems to break Pinephone display or LCDC

H. Nikolaus Schaller hns at goldelico.com
Tue Feb 2 10:18:02 CET 2021


Hi,
since v5.11-rc6 my Pinephone display shows some moiré pattern.

I did a bisect between v5.11-rc5 and v5.11-rc6 and it told me that
the commit mentioned in the subject is the reason.

Reverting it makes the display work again and re-reverting fail again.

IMHO it seems as if the display DMA of the pinephone (allwinner suni-a54)
got influenced and stopped to scan the framebuffer.

The only dma-ranges I could find are defined here:

	arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi

	dma-ranges = <0x00000000 0x40000000 0xc0000000>;

but I can't tell if they are "valid" or not.

Any insights are welcome. And please direct to the right people/mailing lists
if they are missing.

BR and thanks,
Nikolaus Schaller



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