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charset=us-ascii Content-Disposition: inline In-Reply-To: <3c36959a51788bbc5d08f364fe7d922b5c4d4d87.1794633179.git.rosenp@gmail.com> X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-BWhitelist: no X-Source-IP: 108.223.40.66 X-Source-L: No X-Exim-ID: 1xSGy6-00000000Nu5-3izz X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: 108-223-40-66.lightspeed.sntcca.sbcglobal.net (server.roeck-us.net) [108.223.40.66]:33524 X-Source-Auth: guenter@roeck-us.net X-Email-Count: 131 X-Org: HG=direseller_whb_net_legacy;ORG=directi; X-Source-Cap: cm9lY2s7YWN0aXZzdG07YmgtMjUud2ViaG9zdGJveC5uZXQ= X-Local-Domain: yes X-CMAE-Envelope: MS4xfN3pafcd8tZ4QovJ5y1UZxQfKVpbCawqknuKhZ+8QOMyM3vy7CtZ67hE7GB9Wuxp8baXPwXDY3ZiEandXfJEMr1RlY95v/kap62O1116+8wtt7/xdit4 SNjLNwk/038WrghDAJXvIn8t8ZWU3mikdDq4xBJpSmWxMeMeuXwzvVymGB9p4GY6OFtKA0g9f1ODbt0bParwR6w7ZxX/z7/ZR7EBMsPrBD/dD/47IBvhVV8E On Fri, Nov 13, 2026 at 10:20:22PM -0800, Rosen Penev wrote: > dell_smm_write() scales the value written to pwmN with > > DIV_ROUND_CLOSEST(val, data->i8k_pwm_mult) > > before clamping the result to the valid fan states. The rounding adds > i8k_pwm_mult / 2 to val first, which overflows for values near > LONG_MAX and wraps to a large negative number. That is then clamped to > 0, so writing a huge value turns the fan off instead of running it at > the highest speed. With the default fan_max of 2, writing any value > from LONG_MAX - 63 up to LONG_MAX selects fan state 0. > > Clamp val to the pwm range of 0 to 255 first. > > Fixes: e7f5f275c62a ("i8k: Implement hwmon based fan speed control") > Signed-off-by: Rosen Penev > --- > drivers/hwmon/dell-smm-hwmon.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c > index 5ec487843faa..e8b4e8a29e8b 100644 > --- a/drivers/hwmon/dell-smm-hwmon.c > +++ b/drivers/hwmon/dell-smm-hwmon.c > @@ -1030,6 +1030,7 @@ static int dell_smm_write(struct device *dev, enum hwmon_sensor_types type, u32 > case hwmon_pwm: > switch (attr) { > case hwmon_pwm_input: > + val = clamp_val(val, 0, 255); Per convention, invalid pwm value writes should return -EINVAL (because the range is well defined, unlike other limits which are chip dependent). Thanks, Guenter