| Message ID | 1342559541-22421-1-git-send-email-dh.herrmann@googlemail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Jiri Kosina |
| Headers | show |
Hi David, > 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@googlemail.com> > --- > 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? Gladly, but I would like to change the wording slightly, since a driver with raw_event set is a listener, and we are still bailing out if there are no listeners at all. The title is thus misleading. > > 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. */ How about "Drivers using raw_event() are not required to connect to anything else"? > + 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 > Thanks, Henrik -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, 17 Jul 2012, Henrik Rydberg wrote: > > 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@googlemail.com> > > --- > > 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? > > Gladly, but I would like to change the wording slightly, since a driver > with raw_event set is a listener, and we are still bailing out if > there are no listeners at all. The title is thus misleading. So could you guys please come up with a revised version of the patch? I like the aproach much more than the previous one, so would like to queue it for 3.6 merge window. Thanks,
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;
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@googlemail.com> --- 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(-)