I will have closer look on why acpi_match_device could fail. This patch was only based on code reading when trying to fix the compiler warning mentioned in the commit message. [Sorry for top posting] On Sat, Dec 20, 2014 at 11:29 PM, Pandruvada, Srinivas <srinivas.pandruvada@xxxxxxxxx> 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 <knaack.h@xxxxxx> 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. >> >> Thanks, >> Srinivas >> >> > >> 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.purdila@xxxxxxxxx> >> > >> Signed-off-by: Daniel Baluta <daniel.baluta@xxxxxxxxx> >> > >> --- >> > >> 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. >> > -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
