[PATCH 4.14 19/42] usb: gadget: f_hid: added GET_IDLE and SET_IDLE handlers

Greg Kroah-Hartman
2021-08-13T15:15:46Z

From: Maxim Devaev <mdevaev@gmail.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@kernel.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Maxim Devaev <mdevaev@gmail.com>
Link: https://lore.kernel.org/r/20210721180351.129450-1-mdevaev@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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
@@ -45,6 +45,7 @@ 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;
@@ -533,6 +534,14 @@ 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);
@@ -556,6 +565,14 @@ 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) {
@@ -783,6 +800,7 @@ 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);