On Fri, May 13, 2022 at 12:26 PM Saravana Kannan <saravanak@xxxxxxxxxx> wrote: > > On Fri, May 13, 2022 at 6:58 AM Rob Herring <robh@xxxxxxxxxx> wrote: > > > > On Fri, Apr 29, 2022 at 5:09 PM Saravana Kannan <saravanak@xxxxxxxxxx> wrote: > > > > > > The deferred probe timer that's used for this currently starts at > > > late_initcall and runs for driver_deferred_probe_timeout seconds. The > > > assumption being that all available drivers would be loaded and > > > registered before the timer expires. This means, the > > > driver_deferred_probe_timeout has to be pretty large for it to cover the > > > worst case. But if we set the default value for it to cover the worst > > > case, it would significantly slow down the average case. For this > > > reason, the default value is set to 0. > > > > > > Also, with CONFIG_MODULES=y and the current default values of > > > driver_deferred_probe_timeout=0 and fw_devlink=on, devices with missing > > > drivers will cause their consumer devices to always defer their probes. > > > This is because device links created by fw_devlink defer the probe even > > > before the consumer driver's probe() is called. > > > > > > Instead of a fixed timeout, if we extend an unexpired deferred probe > > > timer on every successful driver registration, with the expectation more > > > modules would be loaded in the near future, then the default value of > > > driver_deferred_probe_timeout only needs to be as long as the worst case > > > time difference between two consecutive module loads. > > > > > > So let's implement that and set the default value to 10 seconds when > > > CONFIG_MODULES=y. > > > > We had to revert a non-zero timeout before (issue with NFS root IIRC). > > Does fw_devlink=on somehow fix that? > > If it's the one where ip autoconfig was timing out, then John Stultz > fixed it by fixing wait_for_device_probe(). > https://lore.kernel.org/all/20200422203245.83244-4-john.stultz@xxxxxxxxxx/ Yeah, that was it. Acked-by: Rob Herring <robh@xxxxxxxxxx>
