From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Herrmann Subject: [PATCH] HID: Allow drivers without listeners to remain on the bus Date: Tue, 17 Jul 2012 23:12:21 +0200 Message-ID: <1342559541-22421-1-git-send-email-dh.herrmann@googlemail.com> Return-path: Received: from mail-wg0-f42.google.com ([74.125.82.42]:52706 "EHLO mail-wg0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752464Ab2GQVMV (ORCPT ); Tue, 17 Jul 2012 17:12:21 -0400 Received: by wgbfm10 with SMTP id fm10so3590470wgb.1 for ; Tue, 17 Jul 2012 14:12:20 -0700 (PDT) Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: linux-input@vger.kernel.org Cc: jkosina@suse.cz, rydberg@euromail.se, David Herrmann 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 --- 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