On Mon, 11 Oct 2021 at 09:09, Arnd Bergmann <arnd@xxxxxxxx> wrote: > > On Mon, Oct 11, 2021 at 6:11 AM Dmitry Baryshkov > <dmitry.baryshkov@xxxxxxxxxx> wrote: > > On Sun, 10 Oct 2021 at 20:42, Arnd Bergmann <arnd@xxxxxxxx> wrote: > > > > The patch seems correct, but it becomes overcomplicated. What about: > > - restoring QCOM_SCM stubs > > The stubs are what has led to the previous bugs in this area to often > go unnoticed for too long, as illustrated by your suggestion > > > - making ARM_SMMU select QCOM_SCM if ARM_SMMU_QCOM > > I assume you meant "select QCOM_SCM if ARCH_QCOM", > after we stop using ARM_SMMU_QCOM? > > > This would have almost the same result as with your patch, but without > > extra ARM_SMMU_QCOM Kconfig symbol. > > The "almost" is the problem: consider the case of > > CONFIG_ARM=y > CONFIG_COMPILE_TEST=y > CONFIG_ARCH_QCOM=n > CONFIG_ARM_SMMU=y > CONFIG_DRM_MSM=m > CONFIG_QCOM_SCM=m (selected by DRM_MSM) > > The stubs here lead to ARM_SMMU linking against the QCOM_SCM > driver from built-in code, which fails because QCOM_SCM itself > is a loadable module. I see. The idealist in me wishes to change my suggestion to 'select QCOM_SCM if ARCH_QCOM || COMPILE_TEST' but I have the subtle feeling that this also might fail somehow. > > We can move the "select QCOM_SCM" in the ARM_SMMU_QCOM > symbol if we make that a tristate though, if you want to separate it > a little more. This would complicate things a bit, as we would no longer be able to use 'arm-smmu-$(CONFIG_ARM_SMMU_QCOM) +=' construct. -- With best wishes Dmitry
