Re: [PATCH v2] HID: input: do not run GET_REPORT unless there's a Resolution Multiplier

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 <redacted>
Tested-by: Wen He <redacted>
---
Changes to v1:
- bail out in case of HID_QUIRK_NO_INIT_REPORTS

Applied, thanks Peter.

-- 
Jiri Kosina
SUSE Labs