@@ -837,13 +837,16 @@ static int hidpp_root_get_feature(struct hidpp_device *hidpp, u16 feature,
static int hidpp_root_get_protocol_version(struct hidpp_device *hidpp)
{
+ const u8 ping_byte = 0x5a;
+ u8 ping_data[3] = { 0, 0, ping_byte };
struct hidpp_report response;
int ret;
- ret = hidpp_send_fap_command_sync(hidpp,
+ ret = hidpp_send_rap_command_sync(hidpp,
+ REPORT_ID_HIDPP_SHORT,
HIDPP_PAGE_ROOT_IDX,
CMD_ROOT_GET_PROTOCOL_VERSION,
- NULL, 0, &response);
+ ping_data, sizeof(ping_data), &response);
if (ret == HIDPP_ERROR_INVALID_SUBID) {
hidpp->protocol_major = 1;
@@ -863,8 +866,14 @@ static int hidpp_root_get_protocol_version(struct hidpp_device *hidpp)
if (ret)
return ret;
- hidpp->protocol_major = response.fap.params[0];
- hidpp->protocol_minor = response.fap.params[1];
+ if (response.rap.params[2] != ping_byte) {
+ hid_err(hidpp->hid_dev, "%s: ping mismatch 0x%02x != 0x%02x\n",
+ __func__, response.rap.params[2], ping_byte);
+ return -EPROTO;
+ }
+
+ hidpp->protocol_major = response.rap.params[0];
+ hidpp->protocol_minor = response.rap.params[1];
print_version:
hid_info(hidpp->hid_dev, "HID++ %u.%u device connected.\n",
According to the logitech_hidpp_2.0_specification_draft_2012-06-04.pdf doc: https://lekensteyn.nl/files/logitech/logitech_hidpp_2.0_specification_draft_2012-06-04.pdf We should use a register-access-protocol request using the short input / output report ids. This is necessary because 27MHz HID++ receivers have a max-packetsize on their HIP++ endpoint of 8, so they cannot support long reports. Using a feature-access-protocol request (which is always long or very-long) with these will cause a timeout error, followed by the hidpp driver treating the device as not being HID++ capable. This commit fixes this by switching to using a rap request to get the protocol version. Besides being tested with a (046d:c517) 27MHz receiver with various 27MHz keyboards and mice, this has also been tested to not cause regressions on a non-unifying dual-HID++ nano receiver (046d:c534) with k270 and m185 HID++-2.0 devices connected and on a unifying/dj receiver (046d:c52b) with a HID++-2.0 Logitech Rechargeable Touchpad T650. Signed-off-by: Hans de Goede <hdegoede@redhat.com> --- drivers/hid/hid-logitech-hidpp.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-)