On Thu, Aug 3, 2023 at 9:42 AM Aleksandr Nogikh <nogikh@xxxxxxxxxx> wrote: > > Hello, > > We've been seing the following linker error on arm64 syzbot instances: > > ld.lld: error: undefined symbol: phy_mipi_dphy_get_default_config_for_hsclk > >>> referenced by samsung-dsim.c:731 (drivers/gpu/drm/bridge/samsung-dsim.c:731) > >>> drivers/gpu/drm/bridge/samsung-dsim.o:(samsung_dsim_init) in archive vmlinux.a > > Steps to reproduce on the latest linux-next: > > $ git checkout next-20230803 > $ wget -O '.config' 'https://raw.githubusercontent.com/google/syzkaller/master/dashboard/config/linux/upstream-arm64-kasan.config' > $ make CC=clang ARCH=arm64 LD=ld.lld CROSS_COMPILE=aarch64-linux-gnu- olddefconfig > > This also prints: > > WARNING: unmet direct dependencies detected for GENERIC_PHY_MIPI_DPHY > Depends on [n]: GENERIC_PHY [=n] > Selected by [y]: > - DRM_NWL_MIPI_DSI [=y] && DRM_BRIDGE [=y] && DRM [=y] && COMMON_CLK [=y] && OF [=y] && HAS_IOMEM [=y] > - DRM_SAMSUNG_DSIM [=y] && DRM [=y] && DRM_BRIDGE [=y] && COMMON_CLK [=y] && OF [=y] && HAS_IOMEM [=y] > > $ make CC=clang ARCH=arm64 LD=ld.lld CROSS_COMPILE=aarch64-linux-gnu- -j$(nproc) > > The kernel should have still compiled fine even despite the message above, right? > > Could you please take a look? GENERIC_PHY_MIPI_DPHY was enabled to use phy_mipi_dphy_get_default_config() which takes in the pixel clock, bits-per-pixel, number of lanes and phy structure. It applies a bunch of math based on the info passed and fills in the structure, but that function itself doesn't appear to be referencing phy code, so it's likely safe. I think this can be resolved by enabling GENERIC_PHY. I just checked linux-next and when I built the arm64 defconfig, it enables GENERIC_PHY=y, so I don't think this is an issue. I also checked the multi_v7_defconfig for ARM and it also sets GENERIC_PHY=y for 32-bit ARM people using some of the Exynos boards. I don't know what version of Linux you're trying to build, but I can't replicate your issue. adam > > -- > Thank you! > Aleksandr
