On Mon, Aug 13, 2018 at 7:40 PM Rishabh Bhatnagar <risha...@quicinc.com> wrote: > > From: Rishabh Bhatnagar <risha...@codeaurora.org> > > Drivers that are registered at an initcall level may have to > wait until late_init before the probe deferral mechanism can > retry their probe functions. It is possible that their > dependencies were resolved much earlier, in some cases even > before the next initcall level. Invoke one probe retry cycle > at every _sync initcall level after subsys initcall, allowing > these drivers to be probed earlier. > To give an example many Qualcomm drivers are dependent on the > regulator and bus driver. Both the regulator and bus driver > are probed in the subsys_initcall level. Now the probe of bus > driver requires regulator to be working. If the probe of bus > driver happens before regulator, then bus driver's probe will > be deferred and all other device's probes which depend on bus > driver will also be deferred. > The impact of this problem is reduced if we have this patch. > > Signed-off-by: Vikram Mulukutla <mark...@codeaurora.org> > Signed-off-by: Rishabh Bhatnagar <risha...@codeaurora.org> > --- > > Changes since v0: > * Remove arch_initcall_sync(deferred_probe_initcall) from patch. This is not > really needed as none of the devices are re-probed in arch_initcall_sync > level. > > drivers/base/dd.c | 32 ++++++++++++++++++++++++++------ > 1 file changed, 26 insertions(+), 6 deletions(-) > > diff --git a/drivers/base/dd.c b/drivers/base/dd.c > index 1435d72..9aa41aa 100644 > --- a/drivers/base/dd.c > +++ b/drivers/base/dd.c > @@ -224,23 +224,43 @@ void device_unblock_probing(void) > driver_deferred_probe_trigger(); > } > > +static void enable_trigger_defer_cycle(void) > +{ > + driver_deferred_probe_enable = true;
Isn't it sufficient to enable it once? > + driver_deferred_probe_trigger(); > + /* > + * Sort as many dependencies as possible before the next initcall > + * level > + */ > + flush_work(&deferred_probe_work); > +} I would call this function driver_deferred_probe_sync() or similar to indicate that it is a synchronization point. Thanks, Rafael