On Wed, Aug 1, 2018 at 11:18 PM, <[email protected]> wrote: > On 2018-07-24 01:24, Rafael J. Wysocki wrote: >> >> On Mon, Jul 23, 2018 at 10:22 PM, <[email protected]> wrote: >>> >>> On 2018-07-23 04:17, Rafael J. Wysocki wrote: >>>> >>>> >>>> On Thu, Jul 19, 2018 at 11:24 PM, Rishabh Bhatnagar >>>> <[email protected]> wrote: >>>>> >>>>> >>>>> 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, allowing these drivers to be >>>>> probed earlier. >>>> >>>> >>>> >>>> Can you please say something about the actual use case this is >>>> expected to address? >>> >>> >>> We have a display driver that depends 3 other devices to be >>> probed so that it can bring-up the display. Because of dependencies >>> not being met the deferral mechanism defers the probes for a later time, >>> even though the dependencies might be met earlier. With this change >>> display can be brought up much earlier. >> >> >> OK >> >> What runlevel brings up the display after the change? >> >> Thanks, >> Rafael > > After the change the display can come up after device_initcall level > itself. > The above mentioned 3 devices are probed at 0.503253, 0.505210 and 0.523264 > secs. > Only the first device is probed successfully. With the current > deferral mechanism the devices get probed again after late_initcall > at 9.19 and 9.35 secs. So display can only come up after 9.35 secs. > With this change the devices are re-probed successfully at 0.60 and > 0.613 secs. Therefore display can come just after 0.613 secs.
OK, so why do you touch the initcall levels earlier than device_? > This change helps in overall android bootup as well. How exactly?
