hid-multitouch currently runs GET_REPORT for Contact Max and again to
retrieve the Win8 blob. If both are within the same report, the
Resolution Multiplier code calls GET_FEATURE again and this time,
possibly due to timing, it causes the ILITEK-TP device interpret the
GET_FEATURE as an instruction to change the mode and effectively stop
the device from functioning as expected.
Notably: the device doesn't even have a Resolution Multiplier so it
shouldn't be affected by any of this at all.
Fix this by making sure we only execute GET_REPORT if there is
a Resolution Multiplier in the respective report. Where the
HID_QUIRK_NO_INIT_REPORTS field is set we just bail out immediately. This
shouldn't be triggered by any real device anyway.
Signed-off-by: Peter Hutterer <peter.hutterer@xxxxxxxxx>
Tested-by: Wen He <wen.he_1@xxxxxxx>
---
Changes to v1:
- bail out in case of HID_QUIRK_NO_INIT_REPORTS
drivers/hid/hid-input.c | 30 ++++++++++++++++++++----------
1 file changed, 20 insertions(+), 10 deletions(-)
diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index dea9cc65bf80..c8633beae260 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -1560,21 +1560,12 @@ static bool __hidinput_change_resolution_multipliers(struct hid_device *hid,
{
struct hid_usage *usage;
bool update_needed = false;
+ bool get_report_completed = false;
int i, j;
if (report->maxfield == 0)
return false;
- /*
- * If we have more than one feature within this report we
- * need to fill in the bits from the others before we can
- * overwrite the ones for the Resolution Multiplier.
- */
- if (report->maxfield > 1) {
- hid_hw_request(hid, report, HID_REQ_GET_REPORT);
- hid_hw_wait(hid);
- }
-
for (i = 0; i < report->maxfield; i++) {
__s32 value = use_logical_max ?
report->field[i]->logical_maximum :
@@ -1593,6 +1584,25 @@ static bool __hidinput_change_resolution_multipliers(struct hid_device *hid,
if (usage->hid != HID_GD_RESOLUTION_MULTIPLIER)
continue;
+ /*
+ * If we have more than one feature within this
+ * report we need to fill in the bits from the
+ * others before we can overwrite the ones for the
+ * Resolution Multiplier.
+ *
+ * But if we're not allowed to read from the device,
+ * we just bail. Such a device should not exist
+ * anyway.
+ */
+ if (!get_report_completed && report->maxfield > 1) {
+ if (hid->quirks & HID_QUIRK_NO_INIT_REPORTS)
+ return update_needed;
+
+ hid_hw_request(hid, report, HID_REQ_GET_REPORT);
+ hid_hw_wait(hid);
+ get_report_completed = true;
+ }
+
report->field[i]->value[j] = value;
update_needed = true;
}
--
2.26.2
