Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH 02/13] driver-core: defer all probes until late_initcall | Date | Sat, 20 Jun 2015 01:20:46 +0200 |
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On Friday, June 19, 2015 03:36:46 PM Tomeu Vizoso wrote: > On 18 June 2015 at 23:50, Rafael J. Wysocki <rjw@rjwysocki.net> wrote: > > On Wednesday, June 17, 2015 03:42:12 PM Tomeu Vizoso wrote: > >> To decrease the chances of devices deferring their probes because of > >> dependencies not having probed yet because of their drivers not having > >> registered yet, delay all probing until the late initcall level. > >> > >> This will allow us to avoid deferred probes completely later by probing > >> dependencies on demand, or by probing them in dependency order. > >> > >> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com> > >> --- > >> drivers/base/dd.c | 8 +++++++- > >> 1 file changed, 7 insertions(+), 1 deletion(-) > >> > >> diff --git a/drivers/base/dd.c b/drivers/base/dd.c > >> index a638bbb..18438aa 100644 > >> --- a/drivers/base/dd.c > >> +++ b/drivers/base/dd.c > >> @@ -407,6 +407,12 @@ int driver_probe_device(struct device_driver *drv, struct device *dev) > >> if (!device_is_registered(dev)) > >> return -ENODEV; > >> > >> + /* Defer all probes until we start processing the queue */ > >> + if (!driver_deferred_probe_enable) { > >> + driver_deferred_probe_add(dev); > > > > Do I think correctly that this will effectively force everybody to use deferred > > probing? > > Guess it depends on the meaning of "using deferred probing". It will > defer the probe of the first device to late_initcall (which will > happen much earlier in time than before), but afterwards all built-in > drivers will be available and depending on the order in which we try > to probe devices, none may actually ask to defer its probe.
So this will break things like the PNP system driver which relies on probing stuff at the fs_initcall stage for correctness. It may also break other things with similar assumptions.
-- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/
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