linux-kernel - [PATCH 5.4 45/85] usb: gadget: f_hid: added GET_IDLE and SET

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Date:   Tue, 10 Aug 2021 19:30:18 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Felipe Balbi <balbi@...nel.org>,
        Maxim Devaev <mdevaev@...il.com>
Subject: [PATCH 5.4 45/85] usb: gadget: f_hid: added GET_IDLE and SET_IDLE handlers

From: Maxim Devaev <mdevaev@...il.com>

commit afcff6dc690e24d636a41fd4bee6057e7c70eebd upstream.

The USB HID standard declares mandatory support for GET_IDLE and SET_IDLE
requests for Boot Keyboard. Most hosts can handle their absence, but others
like some old/strange UEFIs and BIOSes consider this a critical error
and refuse to work with f_hid.

This primitive implementation of saving and returning idle is sufficient
to meet the requirements of the standard and these devices.

Acked-by: Felipe Balbi <balbi@...nel.org>
Cc: stable <stable@...r.kernel.org>
Signed-off-by: Maxim Devaev <mdevaev@...il.com>
Link: https://lore.kernel.org/r/20210721180351.129450-1-mdevaev@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/usb/gadget/function/f_hid.c |   18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

--- a/drivers/usb/gadget/function/f_hid.c
+++ b/drivers/usb/gadget/function/f_hid.c
@@ -41,6 +41,7 @@ struct f_hidg {
 	unsigned char			bInterfaceSubClass;
 	unsigned char			bInterfaceProtocol;
 	unsigned char			protocol;
+	unsigned char			idle;
 	unsigned short			report_desc_length;
 	char				*report_desc;
 	unsigned short			report_length;
@@ -529,6 +530,14 @@ static int hidg_setup(struct usb_functio
 		goto respond;
 		break;
 
+	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
+		  | HID_REQ_GET_IDLE):
+		VDBG(cdev, "get_idle\n");
+		length = min_t(unsigned int, length, 1);
+		((u8 *) req->buf)[0] = hidg->idle;
+		goto respond;
+		break;
+
 	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
 		  | HID_REQ_SET_REPORT):
 		VDBG(cdev, "set_report | wLength=%d\n", ctrl->wLength);
@@ -552,6 +561,14 @@ static int hidg_setup(struct usb_functio
 		goto stall;
 		break;
 
+	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
+		  | HID_REQ_SET_IDLE):
+		VDBG(cdev, "set_idle\n");
+		length = 0;
+		hidg->idle = value;
+		goto respond;
+		break;
+
 	case ((USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_INTERFACE) << 8
 		  | USB_REQ_GET_DESCRIPTOR):
 		switch (value >> 8) {
@@ -779,6 +796,7 @@ static int hidg_bind(struct usb_configur
 	hidg_interface_desc.bInterfaceSubClass = hidg->bInterfaceSubClass;
 	hidg_interface_desc.bInterfaceProtocol = hidg->bInterfaceProtocol;
 	hidg->protocol = HID_REPORT_PROTOCOL;
+	hidg->idle = 1;
 	hidg_ss_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
 	hidg_ss_in_comp_desc.wBytesPerInterval =
 				cpu_to_le16(hidg->report_length);