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Thu, 24 Sep 2026 09:49:39 -0700 (PDT) Sender: Guenter Roeck Date: Thu, 24 Sep 2026 09:49:39 -0700 From: Guenter Roeck To: Emanuel =?iso-8859-1?Q?=C1vila?= Cc: Pali =?iso-8859-1?Q?Roh=E1r?= , linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] hwmon: (dell-smm) Add Dell 16 DC16250 to fan control whitelist Message-ID: <3fc774b4-ee92-437e-a869-c603263ed202@roeck-us.net> References: <20260924044829.2889204-1-avilaemanueel@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260924044829.2889204-1-avilaemanueel@gmail.com> On Thu, Sep 24, 2026 at 01:48:29AM -0300, Emanuel Ávila wrote: > On the Dell 16 DC16250, the BIOS keeps the CPU fan at its highest state > (~4700 RPM) even when the system is idle at 45 °C, and fan speed writes > through pwm1 are overridden by the BIOS within a few seconds. > > The I8K_FAN_30A3_31A3 SMM code pair works on this machine through the > WMI-SMM backend: after writing 1 to pwm1_enable, the fan accepts all > three fan states (0, 128 and 255 via pwm1) and reports matching RPM, > and writing 2 hands control back to the BIOS. > > Tested on BIOS 1.8.1 with kernel 7.1.5 (Pop!_OS 24.04). > > Assisted-by: claude-opus-5-5 > Signed-off-by: Emanuel Ávila > Acked-by: Pali Rohár Applied. Thanks, Guenter