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[ Upstream commitd7428bc26f] 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 commit99c5150058("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. Bug: 176850153 Link: https://www.spinics.net/lists/linux-usb/msg65494.html [1] Reviewed-by: Maciej Żenczykowski <zenczykowski@gmail.com> Acked-by: Felipe Balbi <balbi@kernel.org> Signed-off-by: Maxim Devaev <mdevaev@gmail.com> Link: https://lore.kernel.org/r/20210821134004.363217-1-mdevaev@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of:89ff3dfac6("usb: gadget: f_hid: fix f_hidg lifetime vs cdev") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Lee Jones <joneslee@google.com> Change-Id: I0f5759015f17661fe4fe23a1216f1047978c79b1 Signed-off-by: Lee Jones <joneslee@google.com>
How do I submit patches to Android Common Kernels
-
BEST: Make all of your changes to upstream Linux. If appropriate, backport to the stable releases. These patches will be merged automatically in the corresponding common kernels. If the patch is already in upstream Linux, post a backport of the patch that conforms to the patch requirements below.
- Do not send patches upstream that contain only symbol exports. To be considered for upstream Linux,
additions of
EXPORT_SYMBOL_GPL()require an in-tree modular driver that uses the symbol -- so include the new driver or changes to an existing driver in the same patchset as the export. - When sending patches upstream, the commit message must contain a clear case for why the patch is needed and beneficial to the community. Enabling out-of-tree drivers or functionality is not not a persuasive case.
- Do not send patches upstream that contain only symbol exports. To be considered for upstream Linux,
additions of
-
LESS GOOD: Develop your patches out-of-tree (from an upstream Linux point-of-view). Unless these are fixing an Android-specific bug, these are very unlikely to be accepted unless they have been coordinated with kernel-team@android.com. If you want to proceed, post a patch that conforms to the patch requirements below.
Common Kernel patch requirements
- All patches must conform to the Linux kernel coding standards and pass
script/checkpatch.pl - Patches shall not break gki_defconfig or allmodconfig builds for arm, arm64, x86, x86_64 architectures (see https://source.android.com/setup/build/building-kernels)
- If the patch is not merged from an upstream branch, the subject must be tagged with the type of patch:
UPSTREAM:,BACKPORT:,FROMGIT:,FROMLIST:, orANDROID:. - All patches must have a
Change-Id:tag (see https://gerrit-review.googlesource.com/Documentation/user-changeid.html) - If an Android bug has been assigned, there must be a
Bug:tag. - All patches must have a
Signed-off-by:tag by the author and the submitter
Additional requirements are listed below based on patch type
Requirements for backports from mainline Linux: UPSTREAM:, BACKPORT:
- If the patch is a cherry-pick from Linux mainline with no changes at all
- tag the patch subject with
UPSTREAM:. - add upstream commit information with a
(cherry picked from commit ...)line - Example:
- if the upstream commit message is
- tag the patch subject with
important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
- then Joe Smith would upload the patch for the common kernel as
UPSTREAM: important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
Bug: 135791357
Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
(cherry picked from commit c31e73121f4c1ec41143423ac6ce3ce6dafdcec1)
Signed-off-by: Joe Smith <joe.smith@foo.org>
- If the patch requires any changes from the upstream version, tag the patch with
BACKPORT:instead ofUPSTREAM:.- use the same tags as
UPSTREAM: - add comments about the changes under the
(cherry picked from commit ...)line - Example:
- use the same tags as
BACKPORT: important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
Bug: 135791357
Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
(cherry picked from commit c31e73121f4c1ec41143423ac6ce3ce6dafdcec1)
[joe: Resolved minor conflict in drivers/foo/bar.c ]
Signed-off-by: Joe Smith <joe.smith@foo.org>
Requirements for other backports: FROMGIT:, FROMLIST:,
- If the patch has been merged into an upstream maintainer tree, but has not yet
been merged into Linux mainline
- tag the patch subject with
FROMGIT: - add info on where the patch came from as
(cherry picked from commit <sha1> <repo> <branch>). This must be a stable maintainer branch (not rebased, so don't uselinux-nextfor example). - if changes were required, use
BACKPORT: FROMGIT: - Example:
- if the commit message in the maintainer tree is
- tag the patch subject with
important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
- then Joe Smith would upload the patch for the common kernel as
FROMGIT: important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
Bug: 135791357
(cherry picked from commit 878a2fd9de10b03d11d2f622250285c7e63deace
https://git.kernel.org/pub/scm/linux/kernel/git/foo/bar.git test-branch)
Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
Signed-off-by: Joe Smith <joe.smith@foo.org>
- If the patch has been submitted to LKML, but not accepted into any maintainer tree
- tag the patch subject with
FROMLIST: - add a
Link:tag with a link to the submittal on lore.kernel.org - add a
Bug:tag with the Android bug (required for patches not accepted into a maintainer tree) - if changes were required, use
BACKPORT: FROMLIST: - Example:
- tag the patch subject with
FROMLIST: important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
Bug: 135791357
Link: https://lore.kernel.org/lkml/20190619171517.GA17557@someone.com/
Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
Signed-off-by: Joe Smith <joe.smith@foo.org>
Requirements for Android-specific patches: ANDROID:
- If the patch is fixing a bug to Android-specific code
- tag the patch subject with
ANDROID: - add a
Fixes:tag that cites the patch with the bug - Example:
- tag the patch subject with
ANDROID: fix android-specific bug in foobar.c
This is the detailed description of the important fix
Fixes: 1234abcd2468 ("foobar: add cool feature")
Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
Signed-off-by: Joe Smith <joe.smith@foo.org>
- If the patch is a new feature
- tag the patch subject with
ANDROID: - add a
Bug:tag with the Android bug (required for android-specific features)
- tag the patch subject with