kernel/drivers/usb/gadget/function/u_hid.h, branch linux-6.9.y

usb: gadget: f_hid: optional SETUP/SET_REPORT mode

2021-08-24T13:41:08Z

f_hid provides the OUT Endpoint as only way for receiving reports from the host. SETUP/SET_REPORT method is not supported, and this causes a number of compatibility problems with various host drivers, especially in the case of keyboard emulation using f_hid. - Some hosts do not support the OUT Endpoint and ignore it, so it becomes impossible for the gadget to receive a report from the host. In the case of a keyboard, the gadget loses the ability to receive the status of the LEDs. - Some BIOSes/UEFIs can't work with HID devices with the OUT Endpoint at all. This may be due to their bugs or incomplete implementation of the HID standard. For example, absolutely all Apple UEFIs can't handle the OUT Endpoint if it goes after IN Endpoint in the descriptor and require the reverse order (OUT, IN) which is a violation of the standard. Other hosts either do not initialize gadgets with a descriptor containing the OUT Endpoint completely (like some HP and DELL BIOSes and embedded firmwares like on KVM switches), or initialize them, but will not poll the IN Endpoint. This patch adds configfs option no_out_endpoint=1 to disable the OUT Endpoint and allows f_hid to receive reports from the host via SETUP/SET_REPORT. Previously, there was such a feature in f_hid, but it was replaced by the OUT Endpoint [1] in the commit 99c515005857 ("usb: gadget: hidg: register OUT INT endpoint for SET_REPORT"). So this patch actually returns the removed functionality while making it optional. For backward compatibility reasons, the OUT Endpoint mode remains the default behaviour. - The OUT Endpoint mode provides the report queue and reduces USB overhead (eliminating SETUP routine) on transmitting a report from the host. - If the SETUP/SET_REPORT mode is used, there is no report queue, so the userspace will only read last report. For classic HID devices like keyboards this is not a problem, since it's intended to transmit the status of the LEDs and only the last report is important. This mode provides better compatibility with strange and buggy host drivers. Both modes passed USBCV tests. Checking with the USB protocol analyzer also confirmed that everything is working as it should and the new mode ensures operability in all of the described cases. Link: https://www.spinics.net/lists/linux-usb/msg65494.html [1] Reviewed-by: Maciej Żenczykowski Acked-by: Felipe Balbi Signed-off-by: Maxim Devaev Link: https://lore.kernel.org/r/20210821134004.363217-1-mdevaev@gmail.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: function: Fix inconsistent indent

2021-05-10T09:16:10Z

Remove whitespace before variable Acked-by: Felipe Balbi Signed-off-by: Wei Ming Chen Link: https://lore.kernel.org/r/20210503160927.6482-1-jj251510319013@gmail.com Signed-off-by: Greg Kroah-Hartman

USB: gadget: Use the correct style for SPDX License Identifier

2020-05-05T07:58:49Z

This patch corrects the SPDX License Identifier style in header files related to USB peripheral controller drivers. For C header files Documentation/process/license-rules.rst mandates C-like comments (opposed to C source files where C++ style should be used). Changes made by using a script provided by Joe Perches here: https://lkml.org/lkml/2019/2/7/46. Suggested-by: Joe Perches Signed-off-by: Nishad Kamdar Signed-off-by: Felipe Balbi

usb: gadget: Change Andrzej Pietrasiewicz's e-mail address

2019-02-11T09:12:29Z

My @samusung.com address is going to cease existing soon, so change it to an address which can actually be used to contact me. Signed-off-by: Andrzej Pietrasiewicz Signed-off-by: Felipe Balbi

USB: gadget: function: Remove redundant license text

2017-11-07T14:45:02Z

Now that the SPDX tag is in all USB files, that identifies the license in a specific and legally-defined manner. So the extra GPL text wording can be removed as it is no longer needed at all. This is done on a quest to remove the 700+ different ways that files in the kernel describe the GPL license text. And there's unneeded stuff like the address (sometimes incorrect) for the FSF which is never needed. No copyright headers or other non-license-description text was removed. Cc: Oliver Neukum Cc: Johan Hovold Cc: Jerry Zhang Cc: John Keeping Cc: Krzysztof Opasiak Cc: Abdulhadi Mohamed Cc: Matthew Wilcox Cc: Janusz Dziedzic Acked-by: Felipe Balbi Acked-by: Michal Nazarewicz Acked-by: Laurent Pinchart Acked-by: Vincent Pelletier Signed-off-by: Greg Kroah-Hartman

USB: add SPDX identifiers to all remaining files in drivers/usb/

2017-11-04T10:48:02Z

It's good to have SPDX identifiers in all files to make it easier to audit the kernel tree for correct licenses. Update the drivers/usb/ and include/linux/usb* files with the correct SPDX license identifier based on the license text in the file itself. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This work is based on a script and data from Thomas Gleixner, Philippe Ombredanne, and Kate Stewart. Cc: Thomas Gleixner Cc: Kate Stewart Cc: Philippe Ombredanne Signed-off-by: Greg Kroah-Hartman Acked-by: Felipe Balbi Acked-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman

usb: gadget: hid: add configfs support

2014-11-06T22:18:19Z

Make the hid function available for gadgets composed with configfs. Signed-off-by: Andrzej Pietrasiewicz Signed-off-by: Felipe Balbi

usb: gadget: f_hid: convert to new function interface with backward compatibility

2014-11-06T22:18:18Z

Converting hid to the new function interface requires converting the USB hid's function code and its users. This patch converts the f_hid.c to the new function interface. The file can now be compiled into a separate usb_f_hid.ko module. The old function interface is provided by means of a preprocessor conditional directives. After all users are converted, the old interface can be removed. Signed-off-by: Andrzej Pietrasiewicz Signed-off-by: Felipe Balbi