The LittleSur board is marked for high memory support and therefore clearly must provide a way to have enough memory installed for some to be present outside the low 4GiB physical address range. With the memory map of the BCM1250 SOC it has been built around it means over 1GiB of actual DRAM, as only the first 1GiB is mapped in the low 4GiB physical address range[1]. Complement commit cce335ae47e2 ("[MIPS] 64-bit Sibyte kernels need DMA32.") then and also enable ZONE_DMA32 for LittleSur. References: [1] "BCM1250/BCM1125/BCM1125H User Manual", Revision 1250_1125-UM100-R, Broadcom Corporation, 21 Oct 2002, Section 3: "System Overview", "Memory Map", pp. 34-38 Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxxxxxxxx> Fixes: cce335ae47e2 ("[MIPS] 64-bit Sibyte kernels need DMA32.") --- New in v3. --- arch/mips/Kconfig | 1 + 1 file changed, 1 insertion(+) linux-mips-sibyte-littlesur-zone-dma32.diff Index: linux-20181104-littlesur64-defconfig/arch/mips/Kconfig =================================================================== --- linux-20181104-littlesur64-defconfig.orig/arch/mips/Kconfig +++ linux-20181104-littlesur64-defconfig/arch/mips/Kconfig @@ -805,6 +805,7 @@ config SIBYTE_LITTLESUR select SYS_SUPPORTS_BIG_ENDIAN select SYS_SUPPORTS_HIGHMEM select SYS_SUPPORTS_LITTLE_ENDIAN + select ZONE_DMA32 if 64BIT config SIBYTE_SENTOSA bool "Sibyte BCM91250E-Sentosa"