[PATCH] HID: Allow drivers without listeners to remain on the bus

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



hid-picolcd and hid-wiimote do not allow any of hidinput, hiddev or hidraw
to claim the device but still want to remain on the bus. Hence, if a
driver uses the raw_event callback but no listener claimed the device, we
still leave it on the bus as the driver probably handles everything by
itself.

Under some circumstances (eg., hidinput_connect() fails and raw_event set)
a device may not be left on the bus even though it has no listeners. But
then if hidinput_connect() fails there are bigger issues than a device
that is left unhandled. So we can safely use this heuristic to avoid
adding another flag for special devices like hid-picolcd and hid-wiimote.

This also removes the ugly hack from hid-picolcd as this is no longer
required.

Signed-off-by: David Herrmann <dh.herrmann@xxxxxxxxxxxxxx>
---
Hi Jiri

I posted another patchset that introduced HID_CLAIMED_OTHER to avoid this
heuristic but Henrik convinced me that this trivial check is the cleaner and
less intrusive implementation. If you're interested, the old patchset was here:
  http://thread.gmane.org/gmane.linux.kernel.input/25945

Henrik, can you add your signed-off-by as this was your idea?

Thanks
David

 drivers/hid/hid-core.c    | 8 ++++++--
 drivers/hid/hid-picolcd.c | 4 ----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 9cdc74e..83ca3ba 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1373,8 +1373,12 @@ int hid_connect(struct hid_device *hdev, unsigned int connect_mask)
 	if ((connect_mask & HID_CONNECT_HIDRAW) && !hidraw_connect(hdev))
 		hdev->claimed |= HID_CLAIMED_HIDRAW;
 
-	if (!hdev->claimed) {
-		hid_err(hdev, "claimed by neither input, hiddev nor hidraw\n");
+	/* There are device drivers that do not allow hidinput, hiddev or
+	 * hidraw to be connected but still want to remain on the bus. We
+	 * require that these devices use the raw_event callback. Otherwise, we
+	 * simply remove them from the bus if no listener claimed them. */
+	if (!hdev->claimed && !hdev->driver->raw_event) {
+		hid_err(hdev, "device has no listeners, quitting\n");
 		return -ENODEV;
 	}
 
diff --git a/drivers/hid/hid-picolcd.c b/drivers/hid/hid-picolcd.c
index 45c3433..74c388d 100644
--- a/drivers/hid/hid-picolcd.c
+++ b/drivers/hid/hid-picolcd.c
@@ -2613,11 +2613,7 @@ static int picolcd_probe(struct hid_device *hdev,
 		goto err_cleanup_data;
 	}
 
-	/* We don't use hidinput but hid_hw_start() fails if nothing is
-	 * claimed. So spoof claimed input. */
-	hdev->claimed = HID_CLAIMED_INPUT;
 	error = hid_hw_start(hdev, 0);
-	hdev->claimed = 0;
 	if (error) {
 		hid_err(hdev, "hardware start failed\n");
 		goto err_cleanup_data;
-- 
1.7.11.2

--
To unsubscribe from this list: send the line "unsubscribe linux-input" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Linux Media Devel]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Linux Wireless Networking]     [Linux Omap]

  Powered by Linux