arm64/Kconfig: Don't set DMA_BOUNCE_UNALIGNED_KMALLOC

If enabled, DMA_BOUNCE_UNALIGNED_KMALLOC causes the swiotlb buffers
(64MB, by default) to be allocated, even on systems where the DMA
controller can reach all of RAM. This is a huge amount of RAM to
waste on a device with only 512MB to start with, such as the Zero 2 W.

See: https://github.com/raspberrypi/linux/issues/5975

Signed-off-by: Phil Elwell <phil@raspberrypi.com>
This commit is contained in:
Phil Elwell
2024-02-21 14:16:21 +00:00
committed by Dom Cobley
parent fa4408ab7c
commit 1dfec36c06

View File

@@ -139,7 +139,8 @@ config ARM64
select DCACHE_WORD_ACCESS
select HAVE_EXTRA_IPI_TRACEPOINTS
select DYNAMIC_FTRACE if FUNCTION_TRACER
select DMA_BOUNCE_UNALIGNED_KMALLOC
# Disable this to save 64MB when DMA controllers can reach all of RAM
# select DMA_BOUNCE_UNALIGNED_KMALLOC
select DMA_DIRECT_REMAP
select EDAC_SUPPORT
select FRAME_POINTER