Messages in this thread | | | Date | Fri, 07 Sep 2018 13:34:30 -0700 | From | rishabhb@codeauro ... | Subject | Re: [PATCH v1] dd: Invoke one probe retry cycle after some initcall levels |
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On 2018-08-13 10:39, Rishabh Bhatnagar wrote: > From: Rishabh Bhatnagar <rishabhb@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 <markivx@codeaurora.org> > Signed-off-by: Rishabh Bhatnagar <rishabhb@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; > + driver_deferred_probe_trigger(); > + /* > + * Sort as many dependencies as possible before the next initcall > + * level > + */ > + flush_work(&deferred_probe_work); > +} > + > /** > * deferred_probe_initcall() - Enable probing of deferred devices > * > * We don't want to get in the way when the bulk of drivers are > getting probed. > * Instead, this initcall makes sure that deferred probing is delayed > until > - * late_initcall time. > + * all the registered initcall functions at a particular level are > completed. > + * This function is invoked at every *_initcall_sync level. > */ > static int deferred_probe_initcall(void) > { > - driver_deferred_probe_enable = true; > - driver_deferred_probe_trigger(); > - /* Sort as many dependencies as possible before exiting initcalls */ > - flush_work(&deferred_probe_work); > + enable_trigger_defer_cycle(); > + driver_deferred_probe_enable = false; > + return 0; > +} > +subsys_initcall_sync(deferred_probe_initcall); > +fs_initcall_sync(deferred_probe_initcall); > +device_initcall_sync(deferred_probe_initcall); > + > +static int deferred_probe_enable_fn(void) > +{ > + /* Enable deferred probing for all time */ > + enable_trigger_defer_cycle(); > initcalls_done = true; > return 0; > } > -late_initcall(deferred_probe_initcall); > +late_initcall(deferred_probe_enable_fn); > > /** > * device_is_bound() - Check if device is bound to a driver
Hi Rafael Just a reminder about this patch. Let me know if you want me to add/edit anything else. -Rishabh
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