Re: [PATCH v6 3/4] platform/x86: hp-wmi: Skip zero GPU RPM rows for fan speed delta

[Krishna Chomal <krishna.chomal108@gmail.com>]

On Thu, May 21, 2026 at 07:03:50PM +0530, Radhey Kalra wrote:
>Some Victus fan tables start with a CPU RPM value while the GPU RPM
>field is zero. On board 8A3D the first row is cpu=23, gpu=0, noise=25,
>followed by cpu=24, gpu=22, noise=26.
>
>Derive gpu_delta from the first row that contains a non-zero GPU RPM
>instead of unconditionally using row 0.

I agree, this is essential for fan-control to work sensibly. But I just
want to give Ilpo Jarvinen a quick heads-up because this would likely
cause conflict with foobisdweik's patch [1], as they would (probably)
remove gpu_delta in v2 [2]

[1]: https://lore.kernel.org/platform-driver-x86/20260513193916.84673-3-dweikmferris@gmail.com
[2]: https://lore.kernel.org/platform-driver-x86/ag2DCOGyCt7MBUL6@archlinux

>Signed-off-by: Radhey Kalra <radheykalra901@gmail.com>
>---
> drivers/platform/x86/hp/hp-wmi.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
>diff --git a/drivers/platform/x86/hp/hp-wmi.c b/drivers/platform/x86/hp/hp-wmi.c
>index ae2abb9..dcfffe6 100644
>--- a/drivers/platform/x86/hp/hp-wmi.c
>+++ b/drivers/platform/x86/hp/hp-wmi.c
>@@ -2666,6 +2666,7 @@ static int hp_wmi_setup_fan_settings(struct hp_wmi_hwmon_priv *priv)
> 	u8 min_rpm, max_rpm;
> 	u8 cpu_rpm, gpu_rpm, noise_db;
> 	int gpu_delta, i, num_entries, ret;
>+	bool gpu_delta_found = false;
> 	size_t header_size, entry_size;
>
> 	/* Default behaviour on hwmon init is automatic mode */
>@@ -2706,12 +2707,15 @@ static int hp_wmi_setup_fan_settings(struct hp_wmi_hwmon_priv *priv)
> 			min_rpm = cpu_rpm;
> 		if (cpu_rpm > max_rpm)
> 			max_rpm = cpu_rpm;
>+		if (!gpu_delta_found && gpu_rpm > 0) {
>+			gpu_delta = gpu_rpm - cpu_rpm;
>+			gpu_delta_found = true;
>+		}
> 	}
>
>-	if (min_rpm == U8_MAX || max_rpm == 0)
>+	if (min_rpm == U8_MAX || max_rpm == 0 || !gpu_delta_found)
> 		return -EINVAL;
>
>-	gpu_delta = fan_table->entries[0].gpu_rpm - fan_table->entries[0].cpu_rpm;
> 	priv->min_rpm = min_rpm;
> 	priv->max_rpm = max_rpm;
> 	priv->gpu_delta = gpu_delta;
>-- 
>2.54.0
>