kernel test robot reported build errors (undefined references) that didn't make much sense. After reproducing them, there is also a Kconfig warning that is the root cause of the build errors, so fix that Kconfig problem. Fixes this Kconfig warning: WARNING: unmet direct dependencies detected for CMA Depends on [n]: MMU [=n] Selected by [m]: - DRM_ASPEED_GFX [=m] && HAS_IOMEM [=y] && DRM [=m] && OF [=y] && (COMPILE_TEST [=y] || ARCH_ASPEED) && HAVE_DMA_CONTIGUOUS [=y] and these dependent build errors: (.text+0x10c8c): undefined reference to `start_isolate_page_range' microblaze-linux-ld: (.text+0x10f14): undefined reference to `test_pages_isolated' microblaze-linux-ld: (.text+0x10fd0): undefined reference to `undo_isolate_page_range' Fixes: 76356a966e33 ("drm: aspeed: Clean up Kconfig options") Reported-by: kernel test robot <lkp@xxxxxxxxx> Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Cc: Joel Stanley <joel@xxxxxxxxx> Cc: Andrew Jeffery <andrew@xxxxxxxx> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> Cc: Michal Simek <monstr@xxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx> Cc: linux-mm@xxxxxxxxx Cc: linux-aspeed@xxxxxxxxxxxxxxxx Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx Cc: David Airlie <airlied@xxxxxxxx> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx --- First sent on 2020-09-07. Feel free to fix the Kconfig warning some other way... drivers/gpu/drm/aspeed/Kconfig | 1 + 1 file changed, 1 insertion(+) --- linux-next-20201009.orig/drivers/gpu/drm/aspeed/Kconfig +++ linux-next-20201009/drivers/gpu/drm/aspeed/Kconfig @@ -3,6 +3,7 @@ config DRM_ASPEED_GFX tristate "ASPEED BMC Display Controller" depends on DRM && OF depends on (COMPILE_TEST || ARCH_ASPEED) + depends on MMU select DRM_KMS_HELPER select DRM_KMS_CMA_HELPER select DMA_CMA if HAVE_DMA_CONTIGUOUS