diff options
| author | Zev Weiss | 2022-04-26 20:51:09 -0700 |
|---|---|---|
| committer | Guenter Roeck | 2022-04-27 04:52:18 -0700 |
| commit | 08da09f028043fed9653331ae75bc310411f72e6 (patch) | |
| tree | 084f1682f5bb2cb8dccece5ab76cef1aa7c1c4a9 /drivers/hwmon | |
| parent | 75d2b2b06bd8407d03a3f126bc8b95eb356906c7 (diff) | |
hwmon: (pmbus) delta-ahe50dc-fan: work around hardware quirk
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
Link: https://lore.kernel.org/r/20220427035109.3819-1-zev@bewilderbeest.net
Fixes: d387d88ed045 ("hwmon: (pmbus) Add Delta AHE-50DC fan control module driver")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/hwmon')
| -rw-r--r-- | drivers/hwmon/pmbus/delta-ahe50dc-fan.c | 16 |
1 files changed, 16 insertions, 0 deletions
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, }; |