From f74d9bf539cd7a645655c3135d4203e60d9f6b62 Mon Sep 17 00:00:00 2001
From: Drath <drath@drath.cc>
Date: Sun, 7 Jun 2026 17:50:46 +0200
Subject: [PATCH] set fan curve functionality

---
 include/aio.h | 13 ++++++++++++-
 src/aio.c     | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/include/aio.h b/include/aio.h
index e342c0e..6740b27 100644
--- a/include/aio.h
+++ b/include/aio.h
@@ -10,6 +10,12 @@
 #define AIO_COLOR_WHITE { 255, 255, 255 }
 #define AIO_COLOR_OFF { 0, 0, 0 }
 
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+
+// roughly converts fan speed to duty
+#define SPD2DTY(spd) MAX(0, MIN(spd * 100 / max_fan_speed, 100))
+
 enum aio_pump_mode_t : uint8_t {
 	QUIET,
 	BALANCED,
@@ -29,7 +35,12 @@ struct rgb_t {
 	uint8_t b;
 };
 
-struct aio_t{
+struct curve_point_t {
+	uint8_t temp;
+	uint8_t duty;
+};
+
+struct aio_t {
 	libusb_device_handle* handle;
 	enum aio_pump_mode_t pump_mode;
 	float water_temp;
diff --git a/src/aio.c b/src/aio.c
index 1d45f5c..aa2b116 100644
--- a/src/aio.c
+++ b/src/aio.c
@@ -8,6 +8,9 @@
 static const uint16_t usb_timeout = 250;
 static const uint8_t buf_size = 32; // needs 32 bc of overflow issue on these aios?
 
+static const uint16_t max_fan_speed = 1200;
+static const uint8_t max_curve_points = 7;
+
 // posts cmd to the aio, puts n bytes of response inside resp buffer
 #define POST_AND_GET_RESP(cmd, n) uint8_t req = cmd; uint8_t resp[buf_size]; aio_post(dev, &req, 1, resp, n)
 
@@ -99,6 +102,33 @@ static void aio_set_color(libusb_device_handle* dev, const enum aio_color_mode_t
 	aio_post(dev, req, 2, resp, buf_size);
 }
 
+static void aio_set_fan_curve(libusb_device_handle* dev, const struct curve_point_t *curve, const uint8_t count) {
+	if (count < 1 || count > max_curve_points) {
+		applog(LOG_ERR, "aio: curve must have 1-%d points", max_curve_points);
+		return;
+	}
+
+	struct curve_point_t padded[max_curve_points];
+	for (int i = 0; i < max_curve_points; i++)
+		padded[i] = (i < count) ? curve[i] : curve[count - 1];
+
+	uint8_t req[16], resp[32];
+	req[0] = 0x40;
+
+	// setup request
+	for (int i = 0; i < max_curve_points; i++)
+		req[2 + i] = padded[i].temp;
+	for (int i = 0; i < max_curve_points; i++)
+		req[9 + i] = padded[i].duty;
+
+	// set curve for both fans
+	for (int i = 0; i < 2; i++) {
+		req[1] = i;
+		aio_post(dev, req, sizeof(req), resp, sizeof(resp));
+	}
+	applog(LOG_INF, "set up AIO fan curve");
+}
+
 void aio_detect(struct aio_t *aio, const float t_quiet, const float t_balanced) {
 	libusb_init(NULL);
 	aio->handle = libusb_open_device_with_vid_pid(NULL, AIO_USB_VID, AIO_USB_PID);
@@ -110,6 +140,13 @@ void aio_detect(struct aio_t *aio, const float t_quiet, const float t_balanced)
 	aio->t_q = t_quiet;
 	aio->t_b = t_balanced;
 
+	const struct curve_point_t fan_curve[] = {
+		{ 35, SPD2DTY(480) },
+		{ 39, SPD2DTY(750) },
+		{ 45, SPD2DTY(1000) },
+		{ 48, SPD2DTY(max_fan_speed) }
+	};
+
 	/* detaches other software that might take the device? */
 	if (libusb_kernel_driver_active(aio->handle, 0))
 		libusb_detach_kernel_driver(aio->handle, 0);
@@ -117,6 +154,8 @@ void aio_detect(struct aio_t *aio, const float t_quiet, const float t_balanced)
 	aio_usb_claim(aio->handle);
 	applog(LOG_INF, "found Corsair AIO device at %04x:%04x, fw ver: %s, B mode at %.1fC, Q mode at %.1fC", AIO_USB_VID, AIO_USB_PID, aio_get_firmware_version(aio->handle, (char[16]){0}), aio->t_b, aio->t_q);
 	aio_set_pump_mode(aio->handle, QUIET); // needed for init ig?
+	aio_set_color(aio->handle, AIO_COLOR_FIXED, 0, NULL, 0); // so it doenst complain the func is unused
+	aio_set_fan_curve(aio->handle, fan_curve, sizeof(fan_curve) / sizeof(fan_curve[0]));
 	aio_usb_release(aio->handle);
 }