On Fri, Jul 16, 2021 at 10:01 PM Bjorn Andersson <bjorn.andersson@xxxxxxxxxx> wrote: > On Tue 06 Jul 23:53 CDT 2021, John Stultz wrote: > > Allow the qcom_scm driver to be loadable as a permenent module. > > > > This still uses the "depends on QCOM_SCM || !QCOM_SCM" bit to > > ensure that drivers that call into the qcom_scm driver are > > also built as modules. While not ideal in some cases its the > > only safe way I can find to avoid build errors without having > > those drivers select QCOM_SCM and have to force it on (as > > QCOM_SCM=n can be valid for those drivers). > > > > Reviving this now that Saravana's fw_devlink defaults to on, > > which should avoid loading troubles seen before. > > > > Are you (in this last paragraph) saying that all those who have been > burnt by fw_devlink during the last months and therefor run with it > disabled will have a less fun experience once this is merged? > I guess potentially. So way back when this was originally submitted, some folks had trouble booting if it was set as a module due to it loading due to the deferred_probe_timeout expiring. My attempts to change the default timeout value to be larger ran into trouble, but Saravana's fw_devlink does manage to resolve things properly for this case. But if folks are having issues w/ fw_devlink, and have it disabled, and set QCOM_SCM=m they could still trip over the issue with the timeout firing before it is loaded (especially if they are loading modules from late mounted storage rather than ramdisk). > (I'm picking this up, but I don't fancy the idea that some people are > turning the boot process into a lottery) Me neither, and I definitely think the deferred_probe_timeout logic is way too fragile, which is why I'm eager for fw_devlink as it's a much less racy approach to handling module loading dependencies. So if you want to hold on this, while any remaining fw_devlink issues get sorted, that's fine. But I'd also not cast too much ire at fw_devlink, as the global probe timeout approach for handling optional links isn't great, and we need a better solution. thanks -john
