mirror of
https://github.com/torvalds/linux.git
synced 2026-06-09 23:23:53 +02:00
8d89985641
HID standard allows sending a feature request to the device which is answered by an HID report. uhid implements this by sending a UHID_FEATURE event to user-space which then must answer with UHID_FEATURE_ANSWER. If it doesn't do this in a timely manner, the request is discarded silently. We serialize the feature requests, that is, there is always only a single active feature-request sent to user-space, other requests have to wait. HIDP and USB-HID do it the same way. Because we discard feature-requests silently, we must make sure to match a response to the corresponding request. We use sequence-IDs for this so user-space must copy the ID from the request into the answer. Feature-answers are ignored if they do not contain the same ID as the currently pending feature request. Internally, we must make sure that feature-requests are synchronized with UHID_DESTROY and close() events. We must not dead-lock when closing the HID device, either, so we have to use separate locks. Signed-off-by: David Herrmann <dh.herrmann@googlemail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> |
||
|---|---|---|
| .. | ||
| acpi | ||
| asm-generic | ||
| crypto | ||
| drm | ||
| keys | ||
| linux | ||
| math-emu | ||
| media | ||
| misc | ||
| mtd | ||
| net | ||
| pcmcia | ||
| rdma | ||
| rxrpc | ||
| scsi | ||
| sound | ||
| target | ||
| trace | ||
| video | ||
| xen | ||
| Kbuild | ||