6.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jason Gerecke jason.gerecke@wacom.com
[ Upstream commit 359673ea3a203611b4f6d0f28922a4b9d2cfbcc8 ]
The current dropped packet reporting assumes that all sequence numbers are 16 bits in length. This results in misleading "Dropped" messages if the hardware uses fewer bits. For example, if a tablet uses only 8 bits to store its sequence number, once it rolls over from 255 -> 0, the driver will still be expecting a packet "256". This patch adjusts the logic to reset the next expected packet to logical_minimum whenever it overflows beyond logical_maximum.
Signed-off-by: Jason Gerecke jason.gerecke@wacom.com Tested-by: Joshua Dickens joshua.dickens@wacom.com Fixes: 6d09085b38e5 ("HID: wacom: Adding Support for new usages") Signed-off-by: Jiri Kosina jkosina@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/hid/wacom_wac.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c index d84740be96426..8cf82a5f3a5bf 100644 --- a/drivers/hid/wacom_wac.c +++ b/drivers/hid/wacom_wac.c @@ -2492,9 +2492,14 @@ static void wacom_wac_pen_event(struct hid_device *hdev, struct hid_field *field wacom_wac->hid_data.barrelswitch3 = value; return; case WACOM_HID_WD_SEQUENCENUMBER: - if (wacom_wac->hid_data.sequence_number != value) - hid_warn(hdev, "Dropped %hu packets", (unsigned short)(value - wacom_wac->hid_data.sequence_number)); + if (wacom_wac->hid_data.sequence_number != value) { + int sequence_size = field->logical_maximum - field->logical_minimum + 1; + int drop_count = (value - wacom_wac->hid_data.sequence_number) % sequence_size; + hid_warn(hdev, "Dropped %d packets", drop_count); + } wacom_wac->hid_data.sequence_number = value + 1; + if (wacom_wac->hid_data.sequence_number > field->logical_maximum) + wacom_wac->hid_data.sequence_number = field->logical_minimum; return; }