| Message ID | 20220427035109.3819-1-zev@bewilderbeest.net |
|---|---|
| State | New |
| Headers | show |
| Series | hwmon: (pmbus) delta-ahe50dc-fan: work around hardware quirk | expand |
On Tue, Apr 26, 2022 at 08:51:09PM -0700, Zev Weiss wrote: > CLEAR_FAULTS commands can apparently sometimes trigger catastrophic > power output glitches on the ahe-50dc, so block them from being sent > at all. > > Signed-off-by: Zev Weiss <zev@bewilderbeest.net> > Cc: stable@vger.kernel.org Applied. Thanks, Guenter > --- > drivers/hwmon/pmbus/delta-ahe50dc-fan.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/drivers/hwmon/pmbus/delta-ahe50dc-fan.c b/drivers/hwmon/pmbus/delta-ahe50dc-fan.c > index 40dffd9c4cbf..f546f0c12497 100644 > --- a/drivers/hwmon/pmbus/delta-ahe50dc-fan.c > +++ b/drivers/hwmon/pmbus/delta-ahe50dc-fan.c > @@ -14,6 +14,21 @@ > > #define AHE50DC_PMBUS_READ_TEMP4 0xd0 > > +static int ahe50dc_fan_write_byte(struct i2c_client *client, int page, u8 value) > +{ > + /* > + * The CLEAR_FAULTS operation seems to sometimes (unpredictably, perhaps > + * 5% of the time or so) trigger a problematic phenomenon in which the > + * fan speeds surge momentarily and at least some (perhaps all?) of the > + * system's power outputs experience a glitch. > + * > + * However, according to Delta it should be OK to simply not send any > + * CLEAR_FAULTS commands (the device doesn't seem to be capable of > + * reporting any faults anyway), so just blackhole them unconditionally. > + */ > + return value == PMBUS_CLEAR_FAULTS ? -EOPNOTSUPP : -ENODATA; > +} > + > static int ahe50dc_fan_read_word_data(struct i2c_client *client, int page, int phase, int reg) > { > /* temp1 in (virtual) page 1 is remapped to mfr-specific temp4 */ > @@ -68,6 +83,7 @@ static struct pmbus_driver_info ahe50dc_fan_info = { > PMBUS_HAVE_VIN | PMBUS_HAVE_FAN12 | PMBUS_HAVE_FAN34 | > PMBUS_HAVE_STATUS_FAN12 | PMBUS_HAVE_STATUS_FAN34 | PMBUS_PAGE_VIRTUAL, > .func[1] = PMBUS_HAVE_TEMP | PMBUS_PAGE_VIRTUAL, > + .write_byte = ahe50dc_fan_write_byte, > .read_word_data = ahe50dc_fan_read_word_data, > }; >
diff --git a/drivers/hwmon/pmbus/delta-ahe50dc-fan.c b/drivers/hwmon/pmbus/delta-ahe50dc-fan.c index 40dffd9c4cbf..f546f0c12497 100644 --- a/drivers/hwmon/pmbus/delta-ahe50dc-fan.c +++ b/drivers/hwmon/pmbus/delta-ahe50dc-fan.c @@ -14,6 +14,21 @@ #define AHE50DC_PMBUS_READ_TEMP4 0xd0 +static int ahe50dc_fan_write_byte(struct i2c_client *client, int page, u8 value) +{ + /* + * The CLEAR_FAULTS operation seems to sometimes (unpredictably, perhaps + * 5% of the time or so) trigger a problematic phenomenon in which the + * fan speeds surge momentarily and at least some (perhaps all?) of the + * system's power outputs experience a glitch. + * + * However, according to Delta it should be OK to simply not send any + * CLEAR_FAULTS commands (the device doesn't seem to be capable of + * reporting any faults anyway), so just blackhole them unconditionally. + */ + return value == PMBUS_CLEAR_FAULTS ? -EOPNOTSUPP : -ENODATA; +} + static int ahe50dc_fan_read_word_data(struct i2c_client *client, int page, int phase, int reg) { /* temp1 in (virtual) page 1 is remapped to mfr-specific temp4 */ @@ -68,6 +83,7 @@ static struct pmbus_driver_info ahe50dc_fan_info = { PMBUS_HAVE_VIN | PMBUS_HAVE_FAN12 | PMBUS_HAVE_FAN34 | PMBUS_HAVE_STATUS_FAN12 | PMBUS_HAVE_STATUS_FAN34 | PMBUS_PAGE_VIRTUAL, .func[1] = PMBUS_HAVE_TEMP | PMBUS_PAGE_VIRTUAL, + .write_byte = ahe50dc_fan_write_byte, .read_word_data = ahe50dc_fan_read_word_data, };
CLEAR_FAULTS commands can apparently sometimes trigger catastrophic power output glitches on the ahe-50dc, so block them from being sent at all. Signed-off-by: Zev Weiss <zev@bewilderbeest.net> Cc: stable@vger.kernel.org --- drivers/hwmon/pmbus/delta-ahe50dc-fan.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)