On Mon, Mar 14, 2016 at 9:27 AM, Thierry Reding <thierry.red...@gmail.com> wrote: > On Mon, Mar 14, 2016 at 10:18:19AM +0100, Thierry Reding wrote: >> On Mon, Mar 07, 2016 at 05:19:17PM +0530, Sudip Mukherjee wrote: >> > The variable p is a data structure which is used by the driver core >> > internally and it is not expected that busses will be directly accessing >> > these driver core internal only data. >> > >> > Signed-off-by: Sudip Mukherjee <sudip.mukher...@codethink.co.uk> >> > --- >> > >> > Reference of Greg's comment about it at: >> > https://lkml.org/lkml/2016/3/5/171 >> > >> > drivers/i2c/i2c-core.c | 6 ++++-- >> > 1 file changed, 4 insertions(+), 2 deletions(-) >> > >> > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c >> > index 2949ab3..2f31fb5 100644 >> > --- a/drivers/i2c/i2c-core.c >> > +++ b/drivers/i2c/i2c-core.c >> > @@ -73,6 +73,7 @@ static struct device_type i2c_client_type; >> > static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver >> > *driver); >> > >> > static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE; >> > +static bool is_registered; >> > >> > void i2c_transfer_trace_reg(void) >> > { >> > @@ -1529,7 +1530,7 @@ static int i2c_register_adapter(struct i2c_adapter >> > *adap) >> > int res = 0; >> > >> > /* Can't register until after driver model init */ >> > - if (unlikely(WARN_ON(!i2c_bus_type.p))) { >> > + if (unlikely(WARN_ON(!is_registered))) { >> > res = -EAGAIN; >> > goto out_list; >> > } >> > @@ -1926,7 +1927,7 @@ int i2c_register_driver(struct module *owner, struct >> > i2c_driver *driver) >> > int res; >> > >> > /* Can't register until after driver model init */ >> > - if (unlikely(WARN_ON(!i2c_bus_type.p))) >> > + if (unlikely(WARN_ON(!is_registered))) >> > return -EAGAIN; >> > >> > /* add the driver to the list of i2c drivers in the driver core */ >> > @@ -2118,6 +2119,7 @@ static int __init i2c_init(void) >> > if (IS_ENABLED(CONFIG_OF_DYNAMIC)) >> > WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier)); >> > >> > + is_registered = true; >> > return 0; >> > >> > class_err: >> >> This doesn't work. I see a number of these WARN_ON()s trigger and I >> think the reason is that i2c_init() always fails now. The cause seems to >> be that i2c_init() calls i2c_add_driver(&dummy_driver), which will now >> always fail, because is_register is set to true *after* that call. There >> is no way I see I2C working at all after this patch.
Exactly, and this is resulting in recursive failures on dev platform ending up in boot failure > > FWIW, the below on top of your patch seems to fix things for me. > I too came up with same patch, good that I searched before posting it out. FWIW, it fixes the recursive fault at boot on my arm64 platform. Regards, Sudeep
