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HID: logitech-hidpp: use RAP instead of FAP to get the protocol version

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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>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
This commit is contained in:
Hans de Goede 2019-04-20 13:22:10 +02:00 committed by Benjamin Tissoires
parent e54abaf675
commit 096377525c
1 changed files with 13 additions and 4 deletions
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17
drivers/hid/hid-logitech-hidpp.c
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@ -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",