On 4/19/21 11:40 PM, Randy Dunlap wrote: > On 4/19/21 3:23 AM, Stephen Rothwell wrote: >> Hi all, >> >> Changes since 20210416: >> > > on x86_64: > > when > # CONFIG_BLK_DEV is not set > > > WARNING: unmet direct dependencies detected for LIBNVDIMM > Depends on [n]: PHYS_ADDR_T_64BIT [=y] && HAS_IOMEM [=y] && BLK_DEV [=n] > Selected by [y]: > - BCACHE_NVM_PAGES [=y] && MD [=y] && BCACHE [=y] && PHYS_ADDR_T_64BIT [=y] > > > Full randconfig file is attached. > I need hint from kbuild expert. My original idea to use "select LIBNVDIMM" is to avoid the BCACHE_NVM_PAGES option to disappear if LIBNVDIMM is not enabled. Otherwise if nvdimm driver is not configure, users won't know there is a BCACHE_NVM_PAGES option unless they read bcache Kconfig file. But I see nvdimm's Kconfig, it uses "depends on BLK_DEV", I understand it is acceptable that LIBNVDIMM option to disappear from "make menuconfig" if BLK_DEV is not enabled. For such condition, which one is the proper way to set the dependence ? - Change "select LIBNVDIMM" and "select DAX" to "depends on LIBNVDIMM" and "depends on DAX" in bcache Kconfig - Or change "depends on BLK_DEV" to "select BLK_DEV" in nvdimm Kconfig. I want to ask for a proper way to handle such dependence, and I will follow the guide for now and in future. Thanks in advance for the advice. Coly Li