On Sat, Jan 04, 2020 at 02:19:01AM +0300, Dmitry Osipenko wrote: > 03.01.2020 10:25, Michał Mirosław пишет: > > On Thu, Jan 02, 2020 at 06:17:47PM +0300, Dmitry Osipenko wrote: > >> 31.12.2019 00:02, Michał Mirosław пишет: > >>> On Tue, Dec 24, 2019 at 07:21:05AM +0300, Dmitry Osipenko wrote: > >>>> 24.12.2019 00:32, Michał Mirosław пишет: > >>>>> On Fri, Dec 20, 2019 at 07:31:08AM +0300, Dmitry Osipenko wrote: > >>>>>> 20.12.2019 06:56, Peter Chen пишет: > >>>>>>> On 19-12-20 04:52:38, Dmitry Osipenko wrote: > >>>>> [...] > >>>>>>>> --- a/drivers/usb/chipidea/ci_hdrc_tegra.c > >>>>>>>> +++ b/drivers/usb/chipidea/ci_hdrc_tegra.c > >>>>>>>> @@ -53,6 +53,12 @@ static int tegra_udc_probe(struct platform_device *pdev) > >>>>>>>> struct tegra_udc *udc; > >>>>>>>> int err; > >>>>>>>> > >>>>>>>> + if (IS_MODULE(CONFIG_USB_TEGRA_PHY)) { > >>>>>>>> + err = request_module("phy_tegra_usb"); > >>>>>>>> + if (err) > >>>>>>>> + return err; > >>>>>>>> + } > >>>>>>>> + > >>>>>>> > >>>>>>> Why you do this dependency, if this controller driver can't > >>>>>>> get USB PHY, it should return error. What's the return value > >>>>>>> after calling below: > >>>>>>> > >>>>>>> udc->phy = devm_usb_get_phy_by_phandle(&pdev->dev, "nvidia,phy", 0); > >>>>>> > >>>>>> It returns -EPROBE_DEFER when phy_tegra_usb isn't loaded. > >>>>> > >>>>> How are other driver modules autoloaded? Isn't there an appropriate > >>>>> MODALIAS or MODULE_DEVICE_TABLE in there? > >>>> > >>>> Hello Michał, > >>>> > >>>> The phy_tegra_usb module is fine by itself, it's getting autoloaded. > >>>> > >>>> The problem is that ci_hdrc_tegra module depends on the phy_tegra_usb > >>>> module and thus the PHY module should be loaded before the CI module, > >>>> otherwise CI driver fails with the EPROBE_DEFER. > >>> > >>> Why, then, is CI driver not being probed again after PHY driver loads? > >>> EPROBE_DEFER is what should cause driver core to re-probe a device after > >>> other devices appear (PHY in this case). > >> > >> CI driver is getting re-probed just fine if PHY's driver module is > >> loaded manually after loading the CI's module. This patch removes this > >> necessity to manually load PHY's module. > >> > >> This is just a minor convenience change that brings the CI's driver > >> loading behaviour on par with the behaviour of loading Tegra's EHCI > >> driver module. > > > > I fully understand the goal, but what I'm missing is that why this > > doesn't work out of the box? If the PHY module is autoloaded, and so is > > CI driver, and (as I understand) the driver's probe() correctly returns > > EPROBE_DEFER when PHY is not probed yet, then I guess that means bug > > somewhere else and the patch just covers it up. > > It works out of the box, but it also could work a bit better in a case > of manually reloading modules. Perhaps it should be possible to derive > module dependencies from the Kconfig dependencies, apparently kernel > doesn't support it yet or maybe there is some reason why it can't be done. Kconfig change I'm ok with as it simplifies kernel configuration. The request_module() is something I would advise against, because if I do manual module loading, I usually don't want modules loaded automatically. Best Regards, Michał Mirosław