21.06.2018 17:12, Nikita Yushchenko wrote: >>>> This patches causes a regression on a imx51-babbage running 4.18-rc1: >>>> I get a kernel hang. >>>> >>>> If I revert it on top of 4.18-rc1, then it boots fine and USB host is >>>> functional. >>>> >>>> I understand this patch fixes a kernel hang for you, so which commit >>>> is responsible for the hang you observe? >>>> >> >> I never assumed it was a regression and that USB worked on RDU1 board >> before, so I never tried to see if this was a regression. I can only >> tell you that it hangs as soon as any PORTSC registers are accessed. > > Hang at register access usually means that module that owns the register > is not clocked. On RDU1, call to usb_phy_init() actually calls usb_gen_phy_init() that does regulator_enable() for &vusb_reg and clk_prepare_enable() for &clk_26M_usb. I thing some of these two is actually needed to avoid hang on register access. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
