git: 8f496952e3e6 - main - iichid(4): Always use wMaxInputLength bytes as input report length

The branch main has been updated by wulf:

URL: https://cgit.FreeBSD.org/src/commit/?id=8f496952e3e6cdd531675a44b84b3f1954532afb

commit 8f496952e3e6cdd531675a44b84b3f1954532afb
Author:     Vladimir Kondratyev <wulf@FreeBSD.org>
AuthorDate: 2025-09-22 08:37:19 +0000
Commit:     Vladimir Kondratyev <wulf@FreeBSD.org>
CommitDate: 2025-09-22 08:37:19 +0000

    iichid(4): Always use wMaxInputLength bytes as input report length
    
    Lower values may result in non-acknowledged interrupts. E.g. ITE5570 device
    found in ASUS TUF. Greater values may result in read failures. E.g. GXTP7863
    device found on MateBookPro 2023.
    
    Investigated by:        huanghwh@gmail.com
    PR:             289353
    MFC after:      1 week
    fixes:          36027361f9cf ("iichid: Stop using split I²C bus transactions")
---
 sys/dev/iicbus/iichid.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/sys/dev/iicbus/iichid.c b/sys/dev/iicbus/iichid.c
index fdb4816b8bd9..6d95d6d2d4f8 100644
--- a/sys/dev/iicbus/iichid.c
+++ b/sys/dev/iicbus/iichid.c
@@ -816,12 +816,13 @@ iichid_intr_setup(device_t dev, device_t child __unused, hid_intr_t intr,
 
 	sc = device_get_softc(dev);
 	/*
-	 * Do not rely just on wMaxInputLength, as some devices (which?)
-	 * may set it to a wrong length.  Also find the longest input report
-	 * in report descriptor, and add two for the length field.
+	 * Start with wMaxInputLength to follow HID-over-I2C specs. Than if
+	 * semi-HID device like ietp(4) requested changing of input buffer
+	 * size with report descriptor overloading, find the longest input
+	 * report in the descriptor, and add two for the length field.
 	 */
-	rdesc->rdsize = 2 +
-	    MAX(rdesc->isize, le16toh(sc->desc.wMaxInputLength));
+	rdesc->rdsize = rdesc->rdsize == 0 ?
+	    le16toh(sc->desc.wMaxInputLength) : rdesc->isize + 2;
 	/* Write and get/set_report sizes are limited by I2C-HID protocol. */
 	rdesc->grsize = rdesc->srsize = IICHID_SIZE_MAX;
 	rdesc->wrsize = IICHID_SIZE_MAX;