Re: [PATCH] hwmon: (pmbus) Clear generic status alarms with CLEAR_FAULTS

[Guenter Roeck]

On Mon, Aug 24, 2026 at 11:58:00PM -0700, Vishnu Razdan wrote:
> From: Vishnu Razdan <vrazdan@xxxxxxxxxx>
> 
> Some hwmon alarms fall back to STATUS_WORD summary bits when no
> individual limit alarm is available. On PMBus 1.2 and newer devices,
> pmbus_get_boolean() acknowledges these alarms with the same byte-data
> write used for detailed status registers. For example, PB_STATUS_INPUT
> is 0x2000, so it is truncated to zero when passed to
> _pmbus_write_byte_data(). The resulting write cannot acknowledge the
> input alarm.
> 
> PMBus 1.3 Part II, sections 10.2.4 and 10.2.5, excludes ordinary
> STATUS_BYTE and STATUS_WORD summary bits from individual clearing.
> Their summary bits clear when the underlying status bits clear, so
> changing this to a word-data write would not fix the generic input
> alarm either.
> 
> Use the existing page CLEAR_FAULTS path for generic STATUS_WORD
> alarms, including devices whose status accessor uses STATUS_BYTE.
> Keep individual byte writes for detailed status registers on PMBus
> 1.2 and newer devices. As with the existing older-device fallback,
> CLEAR_FAULTS can clear other latched status; an active condition can
> reassert its status.
> 
> Fixes: 35f165f08950 ("hwmon: (pmbus) Clear pmbus fault/warning bits after read")
> Cc: stable@xxxxxxxxxxxxxxx
> Assisted-by: LLM
> Signed-off-by: Vishnu Razdan <vrazdan@xxxxxxxxxx>

Applied.

Thanks,
Guenter