"maximum number of contacts" usages.
Assume touchpad to be a clickpad if it has only internal button.
Set number of contacts to 5 for touchpads and to 10 for touchscreens.
Check for fetched report length to avoid reading of stalled data.
Fixes Dell Precision 7550 laptop.
Tested by: Shawn Webb <shawn.webb_AT_hardenedbsd_DOT_org>
PR: 257992
(cherry picked from commit 9d04336b61)
In Serial mode, each packet contains information that describes a
single physical contact point. Multiple contacts are streamed
serially. In this mode, devices report all contact information in a
series of packets. The device sends a separate packet for each
concurrent contact.
Serial packet reporting mode is used by post-2014 eGalax touchscreens.
Tested by: Mark Kane <mark_AT_kane_DOT_mn>
(cherry picked from commit 0075742d18)
