[PATCH v4] HID: logitech-dj: Add support for a new lightspeed receiver iteration

[PATCH v4] HID: logitech-dj: Add support for a new lightspeed receiver iteration

[Mavroudis Chatzilazaridis]

The lightspeed receiver for the Pro X Superlight uses 13 byte mouse reports
without a report id. The workaround for such cases has been adjusted to
handle these larger packets.

The device now reports the status of its battery in wireless mode and
libratbag now recognizes the device and it can be configured with Piper.

This receiver has new descriptors, which have been added. The mouse
descriptor has 5 extra vendor defined bytes at the end, while the keyboard
one has a different report layout and minimums/maximums. As such, mice
with key press macros and keyboards that use this receiver misbehave
without them.

Fixes: 9d1bd9346241 ("HID: logitech-dj: Add support for a new lightspeed receiver iteration")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=218172
Link: https://bugzilla.kernel.org/show_bug.cgi?id=218094
Link: https://lore.kernel.org/r/CAOEevLOrTSugnLePJwpcqx2_AacNbBxFZDTqp0Qm_jjVpWKgFQ@mail.gmail.com/
Link: https://lore.kernel.org/r/6929ebbf-f2e0-4cd4-addc-1e33ecf3277f@gmail.com/
Co-developed-by: Filipe Laíns <lains@riseup.net>
Signed-off-by: Filipe Laíns <lains@riseup.net>
Signed-off-by: Mavroudis Chatzilazaridis <mavchatz@protonmail.com>
---
V3 -> V4: Rebased and renamed dev id define from 1_2 to 1_3,
          gaming_kbd_descriptor to kbd_lightspeed_1_3_descriptor
V2 -> V3: Fixed regression which broke keyboard related input
V1 -> V2: Addressed review comment for commit message

 drivers/hid/hid-ids.h         |   1 +
 drivers/hid/hid-logitech-dj.c | 106 ++++++++++++++++++++++++++++++++--
 2 files changed, 103 insertions(+), 4 deletions(-)

diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index 149798754570..25d52024f729 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -911,6 +911,7 @@
 #define USB_DEVICE_ID_LOGITECH_NANO_RECEIVER_LIGHTSPEED_1	0xc539
 #define USB_DEVICE_ID_LOGITECH_NANO_RECEIVER_LIGHTSPEED_1_1	0xc53f
 #define USB_DEVICE_ID_LOGITECH_NANO_RECEIVER_LIGHTSPEED_1_2	0xc543
+#define USB_DEVICE_ID_LOGITECH_NANO_RECEIVER_LIGHTSPEED_1_3	0xc547
 #define USB_DEVICE_ID_LOGITECH_NANO_RECEIVER_POWERPLAY	0xc53a
 #define USB_DEVICE_ID_LOGITECH_BOLT_RECEIVER	0xc548
 #define USB_DEVICE_ID_SPACETRAVELLER	0xc623
diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
index cce54dd9884a..00a975b70f59 100644
--- a/drivers/hid/hid-logitech-dj.c
+++ b/drivers/hid/hid-logitech-dj.c
@@ -116,6 +116,7 @@ enum recvr_type {
 	recvr_type_dj,
 	recvr_type_hidpp,
 	recvr_type_gaming_hidpp,
+	recvr_type_gaming_hidpp_ls_1_3,
 	recvr_type_mouse_only,
 	recvr_type_27mhz,
 	recvr_type_bluetooth,
@@ -211,6 +212,45 @@ static const char kbd_descriptor[] = {
 	0xC0
 };
 
+/* Gaming Keyboard descriptor (1) */
+static const char kbd_lightspeed_1_3_descriptor[] = {
+	0x05, 0x01,		/* Usage Page (Generic Desktop) */
+	0x09, 0x06,		/* Usage (Keyboard)             */
+	0xA1, 0x01,		/* Collection (Application)     */
+	0x85, 0x01,		/*   Report ID (1)              */
+	0x05, 0x07,		/*   Usage Page (Kbrd/Keypad)   */
+	0x19, 0xE0,		/*   Usage Minimum (0xE0)       */
+	0x29, 0xE7,		/*   Usage Maximum (0xE7)       */
+	0x15, 0x00,		/*   Logical Minimum (0)        */
+	0x25, 0x01,		/*   Logical Maximum (1)        */
+	0x75, 0x01,		/*   Report Size (1)            */
+	0x95, 0x08,		/*   Report Count (8)           */
+	0x81, 0x02,		/*   Input (Data,Var)           */
+	0x95, 0x05,		/*   Report Count (5)           */
+	0x05, 0x08,		/*   Usage Page (LEDs)          */
+	0x19, 0x01,		/*   Usage Minimum (Num Lock)   */
+	0x29, 0x05,		/*   Usage Maximum (Kana)       */
+	0x91, 0x02,		/*   Output (Data,Var,Abs)      */
+	0x95, 0x01,		/*   Report Count (1)           */
+	0x75, 0x03,		/*   Report Size (3)            */
+	0x91, 0x03,		/*   Output (Const,Var,Abs)     */
+	0x95, 0x70,		/*   Report Count (112)         */
+	0x75, 0x01,		/*   Report Size (1)            */
+	0x05, 0x07,		/*   Usage Page (Kbrd/Keypad)   */
+	0x19, 0x04,		/*   Usage Minimum (0x04)       */
+	0x29, 0x73,		/*   Usage Maximum (0x73)       */
+	0x81, 0x02,		/*   Input (Data,Var,Abs)       */
+	0x95, 0x05,		/*   Report Count (5)           */
+	0x19, 0x87,		/*   Usage Minimum (0x87)       */
+	0x29, 0x8B,		/*   Usage Maximum (0x8B)       */
+	0x81, 0x02,		/*   Input (Data,Var,Abs)       */
+	0x95, 0x03,		/*   Report Count (3)           */
+	0x19, 0x90,		/*   Usage Minimum (0x90)       */
+	0x29, 0x92,		/*   Usage Maximum (0x92)       */
+	0x81, 0x02,		/*   Input (Data,Var,Abs)       */
+	0xC0,			/* End Collection               */
+};
+
 /* Mouse descriptor (2)     */
 static const char mse_descriptor[] = {
 	0x05, 0x01,		/*  USAGE_PAGE (Generic Desktop)        */
@@ -415,6 +455,51 @@ static const char mse_high_res_descriptor[] = {
 	0xC0,			/*  END_COLLECTION                      */
 };
 
+/* Gaming Mouse descriptor with vendor data (2) */
+static const char mse_high_res_ls_1_3_descriptor[] = {
+	0x05, 0x01,		/* Usage Page (Generic Desktop)         */
+	0x09, 0x02,		/* Usage (Mouse)                        */
+	0xA1, 0x01,		/* Collection (Application)             */
+	0x85, 0x02,		/*   Report ID (2)                      */
+	0x09, 0x01,		/*   Usage (Pointer)                    */
+	0xA1, 0x00,		/*   Collection (Physical)              */
+	0x95, 0x10,		/*     Report Count (16)                */
+	0x75, 0x01,		/*     Report Size (1)                  */
+	0x15, 0x00,		/*     Logical Minimum (0)              */
+	0x25, 0x01,		/*     Logical Maximum (1)              */
+	0x05, 0x09,		/*     Usage Page (Button)              */
+	0x19, 0x01,		/*     Usage Minimum (0x01)             */
+	0x29, 0x10,		/*     Usage Maximum (0x10)             */
+	0x81, 0x02,		/*     Input (Data,Var,Abs)             */
+	0x95, 0x02,		/*     Report Count (2)                 */
+	0x75, 0x10,		/*     Report Size (16)                 */
+	0x16, 0x01, 0x80,	/*     Logical Minimum (-32767)         */
+	0x26, 0xFF, 0x7F,	/*     Logical Maximum (32767)          */
+	0x05, 0x01,		/*     Usage Page (Generic Desktop)     */
+	0x09, 0x30,		/*     Usage (X)                        */
+	0x09, 0x31,		/*     Usage (Y)                        */
+	0x81, 0x06,		/*     Input (Data,Var,Rel)             */
+	0x95, 0x01,		/*     Report Count (1)                 */
+	0x75, 0x08,		/*     Report Size (8)                  */
+	0x15, 0x81,		/*     Logical Minimum (-127)           */
+	0x25, 0x7F,		/*     Logical Maximum (127)            */
+	0x09, 0x38,		/*     Usage (Wheel)                    */
+	0x81, 0x06,		/*     Input (Data,Var,Rel)             */
+	0x95, 0x01,		/*     Report Count (1)                 */
+	0x05, 0x0C,		/*     Usage Page (Consumer)            */
+	0x0A, 0x38, 0x02,	/*     Usage (AC Pan)                   */
+	0x81, 0x06,		/*     Input (Data,Var,Rel)             */
+	0xC0,			/*   End Collection                     */
+	0x06, 0x00, 0xFF,	/*   Usage Page (Vendor Defined 0xFF00) */
+	0x09, 0xF1,		/*   Usage (0xF1)                       */
+	0x75, 0x08,		/*   Report Size (8)                    */
+	0x95, 0x05,		/*   Report Count (5)                   */
+	0x15, 0x00,		/*   Logical Minimum (0)                */
+	0x26, 0xFF, 0x00,	/*   Logical Maximum (255)              */
+	0x81, 0x00,		/*   Input (Data,Array,Abs)             */
+	0xC0,			/* End Collection                       */
+};
+
 /* Consumer Control descriptor (3) */
 static const char consumer_descriptor[] = {
 	0x05, 0x0C,		/* USAGE_PAGE (Consumer Devices)       */
@@ -1426,7 +1511,11 @@ static int logi_dj_ll_parse(struct hid_device *hid)
 	if (djdev->reports_supported & STD_KEYBOARD) {
 		dbg_hid("%s: sending a kbd descriptor, reports_supported: %llx\n",
 			__func__, djdev->reports_supported);
-		rdcat(rdesc, &rsize, kbd_descriptor, sizeof(kbd_descriptor));
+		if (djdev->dj_receiver_dev->type == recvr_type_gaming_hidpp_ls_1_3)
+			rdcat(rdesc, &rsize, kbd_lightspeed_1_3_descriptor,
+			      sizeof(kbd_lightspeed_1_3_descriptor));
+		else
+			rdcat(rdesc, &rsize, kbd_descriptor, sizeof(kbd_descriptor));
 	}
 
 	if (djdev->reports_supported & STD_MOUSE) {
@@ -1436,6 +1525,9 @@ static int logi_dj_ll_parse(struct hid_device *hid)
 		    djdev->dj_receiver_dev->type == recvr_type_mouse_only)
 			rdcat(rdesc, &rsize, mse_high_res_descriptor,
 			      sizeof(mse_high_res_descriptor));
+		else if (djdev->dj_receiver_dev->type == recvr_type_gaming_hidpp_ls_1_3)
+			rdcat(rdesc, &rsize, mse_high_res_ls_1_3_descriptor,
+			      sizeof(mse_high_res_ls_1_3_descriptor));
 		else if (djdev->dj_receiver_dev->type == recvr_type_27mhz)
 			rdcat(rdesc, &rsize, mse_27mhz_descriptor,
 			      sizeof(mse_27mhz_descriptor));
@@ -1695,11 +1787,12 @@ static int logi_dj_raw_event(struct hid_device *hdev,
 		}
 		/*
 		 * Mouse-only receivers send unnumbered mouse data. The 27 MHz
-		 * receiver uses 6 byte packets, the nano receiver 8 bytes.
+		 * receiver uses 6 byte packets, the nano receiver 8 bytes,
+		 * the lightspeed receiver (Pro X Superlight) 13 bytes.
 		 */
 		if (djrcv_dev->unnumbered_application == HID_GD_MOUSE &&
-		    size <= 8) {
-			u8 mouse_report[9];
+		    size <= 13){
+			u8 mouse_report[14];
 
 			/* Prepend report id */
 			mouse_report[0] = REPORT_TYPE_MOUSE;
@@ -1776,6 +1869,7 @@ static int logi_dj_probe(struct hid_device *hdev,
 	case recvr_type_dj:		no_dj_interfaces = 3; break;
 	case recvr_type_hidpp:		no_dj_interfaces = 2; break;
 	case recvr_type_gaming_hidpp:	no_dj_interfaces = 3; break;
+	case recvr_type_gaming_hidpp_ls_1_3: no_dj_interfaces = 3; break;
 	case recvr_type_mouse_only:	no_dj_interfaces = 2; break;
 	case recvr_type_27mhz:		no_dj_interfaces = 2; break;
 	case recvr_type_bluetooth:	no_dj_interfaces = 2; break;
@@ -1987,6 +2081,10 @@ static const struct hid_device_id logi_dj_receivers[] = {
 	  HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH,
 		USB_DEVICE_ID_LOGITECH_NANO_RECEIVER_LIGHTSPEED_1_2),
 	 .driver_data = recvr_type_gaming_hidpp},
+	{ /* Logitech lightspeed receiver (0xc547) */
+	  HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH,
+		USB_DEVICE_ID_LOGITECH_NANO_RECEIVER_LIGHTSPEED_1_3),
+	 .driver_data = recvr_type_gaming_hidpp_ls_1_3},
 
 	{ /* Logitech 27 MHz HID++ 1.0 receiver (0xc513) */
 	  HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH, USB_DEVICE_ID_MX3000_RECEIVER),
-- 
2.43.0

Re: [PATCH v4] HID: logitech-dj: Add support for a new lightspeed receiver iteration

[Stuart]

Thanks for rebasing, testing with a Logitech G915 TKL:
 - All the keys work and the media controls work perfectly too.
 - The battery is detected and the sysfs attributes all look correct.

However, caps lock correctly enables caps lock, but the caps lock
light doesn't respond to it any more (the light works without the
driver).
My laptop's internal keyboard lights up correctly when caps lock is
pressed on either keyboard, but the caps lock light on my G915 TKL
never lights up.

I'm happy to check anything you need for troubleshooting, I'm also
happy to compile more kernels :)

Thanks,
Stuart

Re: [PATCH v4] HID: logitech-dj: Add support for a new lightspeed receiver iteration

[Mavroudis Chatzilazaridis]

Hi,

On 02/09/2025 23.03, Stuart wrote:
> Thanks for rebasing, testing with a Logitech G915 TKL:
>   - All the keys work and the media controls work perfectly too.
>   - The battery is detected and the sysfs attributes all look correct.
> 
> However, caps lock correctly enables caps lock, but the caps lock
> light doesn't respond to it any more (the light works without the
> driver).
> My laptop's internal keyboard lights up correctly when caps lock is
> pressed on either keyboard, but the caps lock light on my G915 TKL
> never lights up.

Thanks for taking the time to test it.

Is your product id the same as the one in the patch or are you modifying 
it before compiling?

> I'm happy to check anything you need for troubleshooting, I'm also
> happy to compile more kernels :)

Can you please dump the HID descriptors from your receiver
(sudo usbhid-dump -m 046d:c547) and share them?

> Thanks,
> Stuart


Thanks again

Re: [PATCH v4] HID: logitech-dj: Add support for a new lightspeed receiver iteration

[Stuart]

> Thanks for taking the time to test it.

No problem, I had a go at this a few years ago and had the same issue
with my patches.
I did email the last Logitech contact I could find associated with the
driver, but he seems to have moved to a different part of the company.

> Is your product id the same as the one in the patch or are you modifying
> it before compiling?

No modifications, it's 046d:c547

> Can you please dump the HID descriptors from your receiver
> (sudo usbhid-dump -m 046d:c547) and share them?

Sure (hoping this doesn't get mangled):

001:003:002:DESCRIPTOR         1756919882.495801
 06 00 FF 09 01 A1 01 85 10 95 06 75 08 15 00 26
 FF 00 09 01 81 00 09 01 91 00 C0 06 00 FF 09 02
 A1 01 85 11 95 13 75 08 15 00 26 FF 00 09 02 81
 00 09 02 91 00 C0

001:003:001:DESCRIPTOR         1756919882.500790
 05 01 09 06 A1 01 85 01 05 07 19 E0 29 E7 15 00
 25 01 75 01 95 08 81 02 95 05 05 08 19 01 29 05
 91 02 95 01 75 03 91 03 95 70 75 01 05 07 19 04
 29 73 81 02 95 05 19 87 29 8B 81 02 95 03 19 90
 29 92 81 02 C0 05 0C 09 01 A1 01 85 03 95 02 75
 10 15 01 26 FF 02 19 01 2A FF 02 81 00 C0 05 01
 09 80 A1 01 85 04 95 01 75 02 15 01 25 03 09 82
 09 81 09 83 81 00 75 01 15 00 25 01 09 9B 81 06
 75 05 81 03 C0

001:003:000:DESCRIPTOR         1756919882.504793
 05 01 09 02 A1 01 09 01 A1 00 95 10 75 01 15 00
 25 01 05 09 19 01 29 10 81 02 95 02 75 10 16 01
 80 26 FF 7F 05 01 09 30 09 31 81 06 95 01 75 08
 15 81 25 7F 09 38 81 06 95 01 05 0C 0A 38 02 81
 06 C0 06 00 FF 09 F1 75 08 95 05 15 00 26 FF 00
 81 00 C0

Re: [PATCH v4] HID: logitech-dj: Add support for a new lightspeed receiver iteration

[Mavroudis Chatzilazaridis]

>> Thanks for taking the time to test it.
> 
> No problem, I had a go at this a few years ago and had the same issue
> with my patches.
> I did email the last Logitech contact I could find associated with the
> driver, but he seems to have moved to a different part of the company.
> 
>> Is your product id the same as the one in the patch or are you modifying
>> it before compiling?
> 
> No modifications, it's 046d:c547

Awesome, thanks!

> 
>> Can you please dump the HID descriptors from your receiver
>> (sudo usbhid-dump -m 046d:c547) and share them?
> 
> Sure (hoping this doesn't get mangled):
> 
> 001:003:002:DESCRIPTOR         1756919882.495801
>  06 00 FF 09 01 A1 01 85 10 95 06 75 08 15 00 26
>  FF 00 09 01 81 00 09 01 91 00 C0 06 00 FF 09 02
>  A1 01 85 11 95 13 75 08 15 00 26 FF 00 09 02 81
>  00 09 02 91 00 C0
> 
> 001:003:001:DESCRIPTOR         1756919882.500790
>  05 01 09 06 A1 01 85 01 05 07 19 E0 29 E7 15 00
>  25 01 75 01 95 08 81 02 95 05 05 08 19 01 29 05
>  91 02 95 01 75 03 91 03 95 70 75 01 05 07 19 04
>  29 73 81 02 95 05 19 87 29 8B 81 02 95 03 19 90
>  29 92 81 02 C0 05 0C 09 01 A1 01 85 03 95 02 75
>  10 15 01 26 FF 02 19 01 2A FF 02 81 00 C0 05 01
>  09 80 A1 01 85 04 95 01 75 02 15 01 25 03 09 82
>  09 81 09 83 81 00 75 01 15 00 25 01 09 9B 81 06
>  75 05 81 03 C0
> 
> 001:003:000:DESCRIPTOR         1756919882.504793
>  05 01 09 02 A1 01 09 01 A1 00 95 10 75 01 15 00
>  25 01 05 09 19 01 29 10 81 02 95 02 75 10 16 01
>  80 26 FF 7F 05 01 09 30 09 31 81 06 95 01 75 08
>  15 81 25 7F 09 38 81 06 95 01 05 0C 0A 38 02 81
>  06 C0 06 00 FF 09 F1 75 08 95 05 15 00 26 FF 00
>  81 00 C0

Alright, the HID report descriptors are identical to mine.

I looked at the descriptors again and I noticed that the report ID for
the LEDs, which was previously 14, is now 1.

Can you apply this on top of the existing changes and test again?

diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
index 00a975b70f59..dd51492258f3 100644
--- a/drivers/hid/hid-logitech-dj.c
+++ b/drivers/hid/hid-logitech-dj.c
@@ -78,6 +78,7 @@
 #define REPORT_TYPE_SYSTEM_CONTROL		0x04
 #define REPORT_TYPE_MEDIA_CENTER		0x08
 #define REPORT_TYPE_LEDS			0x0E
+#define REPORT_TYPE_LEDS_LIGHTSPEED		0x01
 
 /* RF Report types bitfield */
 #define STD_KEYBOARD				BIT(1)
@@ -1455,8 +1456,14 @@ static int logi_dj_ll_raw_request(struct hid_device *hid,
 				count, report_type, reqtype);
 	}
 
-	if (buf[0] != REPORT_TYPE_LEDS)
-		return -EINVAL;
+	/* This Lightspeed receiver type uses a different LED report ID */
+	if (djrcv_dev->type == recvr_type_gaming_hidpp_ls_1_3) {
+		if (buf[0] != REPORT_TYPE_LEDS_LIGHTSPEED)
+			return -EINVAL;
+	} else {
+		if (buf[0] != REPORT_TYPE_LEDS)
+			return -EINVAL;
+	}
 
 	if (djrcv_dev->type != recvr_type_dj && count >= 2) {
 		if (!djrcv_dev->keyboard) {

Re: [PATCH v4] HID: logitech-dj: Add support for a new lightspeed receiver iteration

[Stuart]

> Can you apply this on top of the existing changes and test again?

Unfortunately, no change in behaviour

I forgot to mention in my original testing, I get a warning in my dmesg:
logitech-hidpp-device 0003:046D:408E.0007:
hidpp_root_get_protocol_version: received protocol error 0x08

Thanks,
Stuart

Re: [PATCH v4] HID: logitech-dj: Add support for a new lightspeed receiver iteration

[Mavroudis Chatzilazaridis]

On 2025-09-03 23:40, Stuart wrote:
>> Can you apply this on top of the existing changes and test again?
> 
> Unfortunately, no change in behaviour

Hm. It appears I may have misunderstood how this works. Please undo the 
previous diff and apply the following on top instead:

diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
index 00a975b70f59..4ae67f32e78e 100644
--- a/drivers/hid/hid-logitech-dj.c
+++ b/drivers/hid/hid-logitech-dj.c
@@ -227,6 +227,7 @@ static const char kbd_lightspeed_1_3_descriptor[] = {
 	0x95, 0x08,		/*   Report Count (8)           */
 	0x81, 0x02,		/*   Input (Data,Var)           */
 	0x95, 0x05,		/*   Report Count (5)           */
+	0x85, 0x0E,		/*   Report ID (14)             */
 	0x05, 0x08,		/*   Usage Page (LEDs)          */
 	0x19, 0x01,		/*   Usage Minimum (Num Lock)   */
 	0x29, 0x05,		/*   Usage Maximum (Kana)       */
@@ -236,6 +237,7 @@ static const char kbd_lightspeed_1_3_descriptor[] = {
 	0x91, 0x03,		/*   Output (Const,Var,Abs)     */
 	0x95, 0x70,		/*   Report Count (112)         */
 	0x75, 0x01,		/*   Report Size (1)            */
+	0x85, 0x01,		/*   Report ID (1)              */
 	0x05, 0x07,		/*   Usage Page (Kbrd/Keypad)   */
 	0x19, 0x04,		/*   Usage Minimum (0x04)       */
 	0x29, 0x73,		/*   Usage Maximum (0x73)       */

 
> I forgot to mention in my original testing, I get a warning in my dmesg:
> logitech-hidpp-device 0003:046D:408E.0007:
> hidpp_root_get_protocol_version: received protocol error 0x08

I believe that is normal. If I recall correctly, it just means the 
receiver had trouble identifying a device. I think it happens when the 
devices paired to it disconnect/reconnect.

Can you also dump the HID report descriptors when the keyboard is 
plugged in directly via USB?

Re: [PATCH v4] HID: logitech-dj: Add support for a new lightspeed receiver iteration

[Stuart]

> Hm. It appears I may have misunderstood how this works. Please undo the
> previous diff and apply the following on top instead:

Done, still no change :(

> I think it happens when the devices paired to it disconnect/reconnect.

Yep, that matches

> Can you also dump the HID report descriptors when the keyboard is
> plugged in directly via USB?

Sure (046d:c343):

003:007:002:DESCRIPTOR         1756991366.823468
 06 00 FF 09 01 A1 01 85 10 95 06 75 08 15 00 26
 FF 00 09 01 81 00 09 01 91 00 C0 06 00 FF 09 02
 A1 01 85 11 95 13 75 08 15 00 26 FF 00 09 02 81
 00 09 02 91 00 C0

003:007:001:DESCRIPTOR         1756991366.827464
 05 01 09 02 A1 01 85 02 09 01 A1 00 95 10 75 01
 15 00 25 01 05 09 19 01 29 10 81 02 95 02 75 10
 16 01 80 26 FF 7F 05 01 09 30 09 31 81 06 95 01
 75 08 15 81 25 7F 09 38 81 06 95 01 05 0C 0A 38
 02 81 06 C0 C0 05 0C 09 01 A1 01 85 03 95 02 75
 10 15 01 26 FF 02 19 01 2A FF 02 81 00 C0 05 01
 09 80 A1 01 85 04 95 01 75 02 15 01 25 03 09 82
 09 81 09 83 81 00 75 06 81 03 C0

003:007:000:DESCRIPTOR         1756991366.831465
 05 01 09 06 A1 01 05 07 19 E0 29 E7 15 00 25 01
 75 01 95 08 81 02 95 05 05 08 19 01 29 05 91 02
 95 01 75 03 91 03 95 70 75 01 05 07 19 04 29 73
 81 02 95 05 19 87 29 8B 81 02 95 03 19 90 29 92
 81 02 C0

Re: [PATCH v4] HID: logitech-dj: Add support for a new lightspeed receiver iteration

[Mavroudis Chatzilazaridis]

On 04/09/2025 16.12, Stuart wrote:
>> Hm. It appears I may have misunderstood how this works. Please undo the
>> previous diff and apply the following on top instead:
> 
> Done, still no change :(

Unfortunately I'm out of ideas for now. Looking at it again, I think the
first approach seemed more promising. Perhaps I missed something.

>> I think it happens when the devices paired to it disconnect/reconnect.
> 
> Yep, that matches
> 
>> Can you also dump the HID report descriptors when the keyboard is
>> plugged in directly via USB?
> 
> Sure (046d:c343):
> 
> 003:007:002:DESCRIPTOR         1756991366.823468
>  06 00 FF 09 01 A1 01 85 10 95 06 75 08 15 00 26
>  FF 00 09 01 81 00 09 01 91 00 C0 06 00 FF 09 02
>  A1 01 85 11 95 13 75 08 15 00 26 FF 00 09 02 81
>  00 09 02 91 00 C0
> 
> 003:007:001:DESCRIPTOR         1756991366.827464
>  05 01 09 02 A1 01 85 02 09 01 A1 00 95 10 75 01
>  15 00 25 01 05 09 19 01 29 10 81 02 95 02 75 10
>  16 01 80 26 FF 7F 05 01 09 30 09 31 81 06 95 01
>  75 08 15 81 25 7F 09 38 81 06 95 01 05 0C 0A 38
>  02 81 06 C0 C0 05 0C 09 01 A1 01 85 03 95 02 75
>  10 15 01 26 FF 02 19 01 2A FF 02 81 00 C0 05 01
>  09 80 A1 01 85 04 95 01 75 02 15 01 25 03 09 82
>  09 81 09 83 81 00 75 06 81 03 C0
> 
> 003:007:000:DESCRIPTOR         1756991366.831465
>  05 01 09 06 A1 01 05 07 19 E0 29 E7 15 00 25 01
>  75 01 95 08 81 02 95 05 05 08 19 01 29 05 91 02
>  95 01 75 03 91 03 95 70 75 01 05 07 19 04 29 73
>  81 02 95 05 19 87 29 8B 81 02 95 03 19 90 29 92
>  81 02 C0

I was hoping that would give me a clue, but unfortunately it did not.

I suspect simply sending the LED report to the receiver itself with
Report ID 1 is not enough, which is what the first diff does.

Perhaps you could try a packet capture with the Logitech provided driver
in a VM running a well known commercial operating system + usbmon on the
host to see what HID report actually gets sent.

Re: [PATCH v4] HID: logitech-dj: Add support for a new lightspeed receiver iteration

[Stuart]

What does logitech-dj do differently to the generic HID driver around the LEDs?
The caps lock LED works perfectly fine with the generic driver.

If that goes nowhere, surely I could do a packet capture from Linux, with and
without the logitech-dj driver active?

Stuart

Re: [PATCH v4] HID: logitech-dj: Add support for a new lightspeed receiver iteration

[Mavroudis Chatzilazaridis]

On 2025-09-09 02.59, Stuart wrote:
> What does logitech-dj do differently to the generic HID driver around the LEDs?
> The caps lock LED works perfectly fine with the generic driver.
> 
> If that goes nowhere, surely I could do a packet capture from Linux, with and
> without the logitech-dj driver active?
> 
> Stuart

Since the first diff you tested was supposed to send the exact same 
report as the generic hid driver, I incorrectly came to the conclusion 
that the Logitech kernel driver must be doing something different.

Turns out the report ID was being forced to 0 when it should have been 1.

Can you try applying the following?

diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
index 00a975b70f59..9b3b00d69079 100644
--- a/drivers/hid/hid-logitech-dj.c
+++ b/drivers/hid/hid-logitech-dj.c
@@ -78,6 +78,7 @@
 #define REPORT_TYPE_SYSTEM_CONTROL		0x04
 #define REPORT_TYPE_MEDIA_CENTER		0x08
 #define REPORT_TYPE_LEDS			0x0E
+#define REPORT_TYPE_LEDS_LIGHTSPEED		0x01
 
 /* RF Report types bitfield */
 #define STD_KEYBOARD				BIT(1)
@@ -1455,16 +1456,28 @@ static int logi_dj_ll_raw_request(struct hid_device *hid,
 				count, report_type, reqtype);
 	}
 
-	if (buf[0] != REPORT_TYPE_LEDS)
-		return -EINVAL;
+	/* This Lightspeed receiver type uses a different LED report ID */
+	if (djrcv_dev->type == recvr_type_gaming_hidpp_ls_1_3) {
+		if (buf[0] != REPORT_TYPE_LEDS_LIGHTSPEED)
+			return -EINVAL;
+	} else {
+		if (buf[0] != REPORT_TYPE_LEDS)
+			return -EINVAL;
+	}
 
 	if (djrcv_dev->type != recvr_type_dj && count >= 2) {
+		unsigned char reportnum_led = 0;
 		if (!djrcv_dev->keyboard) {
 			hid_warn(hid, "Received REPORT_TYPE_LEDS request before the keyboard interface was enumerated\n");
 			return 0;
 		}
+
+		/* This Lightspeed receiver expects LED reports with the ID defined in the HID descriptor */
+		if (djrcv_dev->type == recvr_type_gaming_hidpp_ls_1_3)
+			reportnum_led = reportnum;
+
 		/* usbhid overrides the report ID and ignores the first byte */
-		return hid_hw_raw_request(djrcv_dev->keyboard, 0, buf, count,
+		return hid_hw_raw_request(djrcv_dev->keyboard, reportnum_led, buf, count,
 					  report_type, reqtype);
 	}
 

Re: [PATCH v4] HID: logitech-dj: Add support for a new lightspeed receiver iteration

[Stuart]

> Can you try applying the following?

Yep, this on top of the v4 patch works as expected.
Thank you for getting this working.

Tested-by: Stuart Hayhurst <stuart.a.hayhurst@gmail.com>

Thanks,
Stuart