git.openwrt.org Git - openwrt/staging/pepe2k.git/blob

   1 From 953f00c3ceb5879d8f0d2f2683d70ff93efedad4 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.com>
   3 Date: Wed, 21 Feb 2024 14:16:21 +0000
   4 Subject: [PATCH 0908/1085] arm64/Kconfig: Don't set
   5  DMA_BOUNCE_UNALIGNED_KMALLOC
   6
   7 If enabled, DMA_BOUNCE_UNALIGNED_KMALLOC causes the swiotlb buffers
   8 (64MB, by default) to be allocated, even on systems where the DMA
   9 controller can reach all of RAM. This is a huge amount of RAM to
  10 waste on a device with only 512MB to start with, such as the Zero 2 W.
  11
  12 See: https://github.com/raspberrypi/linux/issues/5975
  13
  14 Signed-off-by: Phil Elwell <phil@raspberrypi.com>
  15 ---
  16  arch/arm64/Kconfig | 3 ++-
  17  1 file changed, 2 insertions(+), 1 deletion(-)
  18
  19 --- a/arch/arm64/Kconfig
  20 +++ b/arch/arm64/Kconfig
  21 @@ -122,7 +122,8 @@ config ARM64
  22         select CRC32
  23         select DCACHE_WORD_ACCESS
  24         select DYNAMIC_FTRACE if FUNCTION_TRACER
  25 -       select DMA_BOUNCE_UNALIGNED_KMALLOC
  26 +       # Disable this to save 64MB when DMA controllers can reach all of RAM
  27 +       # select DMA_BOUNCE_UNALIGNED_KMALLOC
  28         select DMA_DIRECT_REMAP
  29         select EDAC_SUPPORT
  30         select FRAME_POINTER