If variable is of Type, use printk format specifier: --------------------------------------------------------- int %d or %x unsigned int %u or %x long %ld or %lx unsigned long %lu or %lx long long %lld or %llx unsigned long long %llu or %llx size_t %zu or %zx ssize_t %zd or %zx Raw pointer value SHOULD be printed with %p. u64 SHOULD be printed with %llu/%llx, (unsigned long long): printk("%llu", (unsigned long long)u64_var); s64 SHOULD be printed with %lld/%llx, (long long): printk("%lld", (long long)s64_var); If is dependent on a config option for its size (e.g., sector_t, blkcnt_t, phys_addr_t, resource_size_t) or is architecture-dependent for its size (e.g., tcflag_t), use a format specifier of its largest possible type and explicitly cast to it. Example: printk("test: sector number/total blocks: %llu/%llu\n", (unsigned long long)sector, (unsigned long long)blockcount); Reminder: sizeof() result is of type size_t. Thank you for your cooperation and attention. By Randy Dunlap