Hi Ulrich,
OK. So I guess the only remaining questions is: if this hardware needs the errata fix to work properly, shouldn't it be automatically selected by the kernel configure logic? Note that this appears to happen for certain OMAP boards, see arch/arm/mach-omap2/Kconfig:
config ARCH_OMAP4 bool "TI OMAP4" default y depends on ARCH_OMAP2PLUS select CPU_V7 select ARM_GIC select PL310_ERRATA_588369 select ARM_ERRATA_720789 <<===== select USB_ARCH_HAS_EHCI
But this does not happen for the vexpress; arch/arm/mach-vexpress/Kconfig has only:
config ARCH_VEXPRESS_CA9X4 bool "Versatile Express Cortex-A9x4 tile" select CPU_V7 select ARM_GIC
Good point. Although the erratum might not apply to the revision of the A9 that you have on that tile, it's probably better to select it by default and let the user deselect it if it's not required (the workarounds which poke chicken bits read the CPUID anyway so we could select those as well).
Will