On Mon, 2015-01-19 at 16:40 +0200, Daniel Baluta wrote: > Hello, > > On Sat, Dec 20, 2014 at 11:29 PM, Pandruvada, Srinivas > <srinivas.pandruv...@intel.com> wrote: > > +Mika > > > > On Sat, 2014-12-20 at 13:26 -0800, Srinivas Pandruvada wrote: > >> On Sat, 2014-12-20 at 00:25 +0200, Daniel Baluta wrote: > >> > On Sat, Dec 20, 2014 at 12:16 AM, Hartmut Knaack <knaac...@gmx.de> wrote: > >> > > Daniel Baluta schrieb am 18.12.2014 um 18:16: > >> > >> When using ACPI, if acpi_match_device fails then chipset enum will be > >> > >> uninitialized and &ak_def_array[chipset] will point to some bad > >> > >> address. > >> > >> > >> I am missing something. You are enumerated over i2c device, which was > >> created from ACPI PNP resource. There is a valid handle or and the > >> device has an ACPI companion at the least. If this failing, I have to > >> check the code for acpi i2c. > >> Can you check why this check failed? We may have bug in i2c handling. > > You are right about this. Under normal circumstances, if probe is called > then acpi_match_device will not fail. I even tried to remove the > device after probe > but before acpi_match_device, anyhow acpi_match_device was still successful :) > > This is more a matter of code correctness. > > In ak8975_match_acpi_device we have: > > » const struct acpi_device_id *id; > > » id = acpi_match_device(dev->driver->acpi_match_table, dev); > » if (!id) > » » return NULL; > » *chipset = (int)id->driver_data; > > Compiler complains on the fact that chipset might be uninitialized > if this returns NULL, and we shouldn't ignore this warning even this case > will never happen. > Will this fix? data->chipset = AK8975; before ak8975_match_acpi_device(&client->dev, &data->chipset);
Thanks, Srinivas > We could use some code injection techniques to force acpi_match_device > to return NULL tough. > > >> > >> This fixes the following compilation warning: > >> > >> > >> > >> drivers/iio/magnetometer/ak8975.c: In function ‘ak8975_probe’: > >> > >> drivers/iio/magnetometer/ak8975.c:788:14: warning: ‘chipset’ may be > >> > >> used > >> > >> uninitialized in this function [-Wmaybe-uninitialized] > >> > >> data->def =ak_def_array[chipset]; > >> > >> > >> > >> Reported-by: Octavian Purdila <octavian.purd...@intel.com> > >> > >> Signed-off-by: Daniel Baluta <daniel.bal...@intel.com> > >> > >> --- > >> > >> This is a RFC because while I'm pretty sure that chipset should be > >> > >> initialized > >> > >> with AK_MAX_TYPE in ak8975_match_acpi_device, I am not sure if we can > >> > >> live with > >> > >> a NULL return value of ak8975_match_acpi_device. Current > >> > >> implementation ignores > >> > >> return value of ak8975_match_acpi_device. > >> > > This seems to be the actual problem: these _match_acpi_device > >> > > functions return > >> > > NULL on failure, and this should be checked for. > >> > > >> > Ok, so this would acceptable? > >> > > >> > diff --git a/drivers/iio/magnetometer/ak8975.c > >> > b/drivers/iio/magnetometer/ak8975.c > >> > index 0d10a4b..68d99e9 100644 > >> > --- a/drivers/iio/magnetometer/ak8975.c > >> > +++ b/drivers/iio/magnetometer/ak8975.c > >> > @@ -776,8 +776,9 @@ static int ak8975_probe(struct i2c_client *client, > >> > name = id->name; > >> > } else if (ACPI_HANDLE(&client->dev)) > >> > name = ak8975_match_acpi_device(&client->dev, &chipset); > >> > - else > >> > - return -ENOSYS; > >> > + > >> > + if (!name) > >> > + return -ENODEV; > >> > > >> > > >> > I still have some doubts about return code in case of error. > >> > > >> > For ak8975 we use -ENOSYS, but for kxcjk-1013 we use -ENODEV. > >> > > >> > I will send a patch after we clear this out. > >> > > >> > thanks, > >> > Daniel. > >> > > N�����r��y����b�X��ǧv�^�){.n�+����{����zX����ܨ}���Ơz�&j:+v�������zZ+��+zf���h���~����i���z��w���?�����&�)ߢf��^jǫy�m��@A�a��� 0��h���i