Unfortunately details of USB HID transport bled into HID core and
handling of numbered/unnumbered reports is quite a mess, with
hid_report_len() calculating the length according to USB rules,
and hid_hw_raw_request() adding report ID to the buffer for both
numbered and unnumbered reports.
Untangling it all requres a lot of changes in HID, so for now let's
handle this in the driver.
Fixes: 14c9c014babe ("HID: add vivaldi HID driver")
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
---
CrOS folks, please help testing this as I do not have the affected
hardware.
Thanks!
drivers/hid/hid-vivaldi.c | 34 ++++++++++++++++++++++++++++------
1 file changed, 28 insertions(+), 6 deletions(-)
diff --git a/drivers/hid/hid-vivaldi.c b/drivers/hid/hid-vivaldi.c
index cd7ada48b1d9..1804de1ef9b8 100644
--- a/drivers/hid/hid-vivaldi.c
+++ b/drivers/hid/hid-vivaldi.c
@@ -71,10 +71,11 @@ static void vivaldi_feature_mapping(struct hid_device *hdev,
struct hid_usage *usage)
{
struct vivaldi_data *drvdata = hid_get_drvdata(hdev);
+ struct hid_report *report = field->report;
int fn_key;
int ret;
u32 report_len;
- u8 *buf;
+ u8 *report_data, *buf;
if (field->logical != HID_USAGE_FN_ROW_PHYSMAP ||
(usage->hid & HID_USAGE_PAGE) != HID_UP_ORDINAL)
@@ -86,12 +87,24 @@ static void vivaldi_feature_mapping(struct hid_device *hdev,
if (fn_key > drvdata->max_function_row_key)
drvdata->max_function_row_key = fn_key;
- buf = hid_alloc_report_buf(field->report, GFP_KERNEL);
- if (!buf)
+ report_data = buf = hid_alloc_report_buf(report, GFP_KERNEL);
+ if (!report_data)
return;
- report_len = hid_report_len(field->report);
- ret = hid_hw_raw_request(hdev, field->report->id, buf,
+ report_len = hid_report_len(report);
+ if (!report->id) {
+ /*
+ * hid_hw_raw_request() will stuff report ID (which will be 0)
+ * into the first byte of the buffer even for unnumbered
+ * reports, so we need to account for this to avoid getting
+ * -EOVERFLOW in return.
+ * Note that hid_alloc_report_buf() adds 7 bytes to the size
+ * so we can safely say that we have space for an extra byte.
+ */
+ report_len++;
+ }
+
+ ret = hid_hw_raw_request(hdev, field->report->id, report_data,
report_len, HID_FEATURE_REPORT,
HID_REQ_GET_REPORT);
if (ret < 0) {
@@ -100,7 +113,16 @@ static void vivaldi_feature_mapping(struct hid_device *hdev,
goto out;
}
- ret = hid_report_raw_event(hdev, HID_FEATURE_REPORT, buf,
+ if (!report->id) {
+ /*
+ * Undo the damage from hid_hw_raw_request() for unnumbered
+ * reports.
+ */
+ report_data++;
+ report_len--;
+ }
+
+ ret = hid_report_raw_event(hdev, HID_FEATURE_REPORT, report_data,
report_len, 0);
if (ret) {
dev_warn(&hdev->dev, "failed to report feature %d\n",
--
2.34.1.575.g55b058a8bb-goog
--
Dmitry
