[PATCH] hid: Add a hid quirk for input sync override

Henrik Rydberg rydberg at euromail.se
Tue Aug 24 14:19:29 UTC 2010

As of lately, HID devices which send per-frame data split over several
HID reports have started to emerge. This patch adds a quirk which
allows the HID driver to take over the input layer synchronization,
and hence the control of the frame boundary.

Signed-off-by: Henrik Rydberg <rydberg at euromail.se>
Ten days ago, there were reports on linux-input about broken
Multitouch HID drivers (egalax, 3m-pct) for new devices, including the
Joojoo. It turns out these are due to a new HID extension, pushed by a
large software company, which sends per-frame data in sequence.

I propose carrying the above patch for Maverick, to enable the process
of analyzing and fixing those drivers using dkms during the beta
cycle. I do not yet know what will happen upstream.


 drivers/hid/hid-input.c |    3 +++
 include/linux/hid.h     |    1 +
 2 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index 69d152e..9d97934 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -656,6 +656,9 @@ void hidinput_report_event(struct hid_device *hid, struct hid_report *report)
 	struct hid_input *hidinput;
+	if (hid->quirks & HID_QUIRK_NO_INPUT_SYNC)
+		return;
 	list_for_each_entry(hidinput, &hid->inputs, list)
diff --git a/include/linux/hid.h b/include/linux/hid.h
index 895001f..8029883 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -315,6 +315,7 @@ struct hid_item {
 #define HID_QUIRK_NO_INIT_REPORTS		0x20000000
 #define HID_QUIRK_NO_IGNORE			0x40000000
+#define HID_QUIRK_NO_INPUT_SYNC			0x80000000
  * This is the global environment of the parser. This information is

More information about the kernel-team mailing list