Message ID | 20200609060319.GA36844@jelly (mailing list archive) |
---|---|
State | Mainlined |
Commit | 1ad273d6ff2d3af6ce3a4c8bd81a2ba10151ae0e |
Delegated to: | Jiri Kosina |
Headers | show |
Series | [v2] HID: input: do not run GET_REPORT unless there's a Resolution Multiplier | expand |
On Tue, 9 Jun 2020, Peter Hutterer wrote: > 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@who-t.net> > Tested-by: Wen He <wen.he_1@nxp.com> > --- > Changes to v1: > - bail out in case of HID_QUIRK_NO_INIT_REPORTS Applied, thanks Peter.
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; }