Handle left and right shift, allow shift+enter.

1 files changed, 29 insertions, 12 deletions

diff --git a/marsond.8 b/marsond.8
index a5c8db1..73df335 100644
--- a/marsond.8
+++ b/marsond.8
@@ -27,9 +27,9 @@ level margin: \\n[rst2man-indent\\n[rst2man-indent-level]]
 .\" new: \\n[rst2man-indent\\n[rst2man-indent-level]]
 .in \\n[rst2man-indent\\n[rst2man-indent-level]]u
 ..
-.TH "MARSOND" 8 "2026-01-05" "0.4.0" "Urchlay's Stuff"
+.TH "MARSOND" 8 "2026-01-06" "0.4.0" "Urchlay's Stuff"
 .SH NAME
-marsond \- Fix Enter key timing on Marson/USBLink/MT606-1 PS/2-USB adaptors
+marsond \- Fix Enter/Shift key timings on Marson/USBLink/MT606-1 PS/2-USB adaptors
 .SH SYNOPSIS
 .sp
 marsond [\fB\-d\fP \fIdelay\-ms\fP] [\fB\-f\fP] [\fB\-k\fP \fIkeyboard\-device\fP] [\fB\-p\fP \fIpause_ms\fP [\fB\-v\fP] | [\fB\-\-help\fP] | [\fB\-\-version\fP] | [\fB\-V\fP]
@@ -43,9 +43,10 @@ In games and emulators, the Enter key only works sometimes. This is
 caused by the firmware in the adaptor sending the keypress and release
 events only 8 milliseconds apart.
 .IP \(bu 2
-In normal use, pressing and releasing the right Shift key and Enter
+In normal use, pressing either Shift key and Enter
 key simultaneously causes the shift key to get "stuck" and act like
-it\(aqs still being held down.
+it\(aqs still being held down. You have to press and release Shift again
+to get it to "unstick".
 .UNINDENT
 .sp
 See the \fBNOTES\fP section for full details.
@@ -67,8 +68,10 @@ Options can be "bundled": \fB\-vf\fP is the same as \fB\-v\fP \fB\-f\fP\&.
 .INDENT 0.0
 .TP
 .BI \-d \ delay\-ms
-Amount of time in milliseconds to delay the Enter key release events.
-Minimum 1, default 30 (unless changed at compile time; see \fB\-\-help\fP).
+Amount of time in milliseconds to delay the Enter key release
+events. Also, the Shift key threshold is this times 4, unless set
+with the \fB\-s\fP option. Minimum 1, default 30 (unless changed at
+compile time; see \fB\-\-help\fP).
 .UNINDENT
 .\" delay time for Enter key release.
 .
@@ -111,6 +114,16 @@ if started manually. Minimum 0, default 0.
 .
 .INDENT 0.0
 .TP
+.BI \-s \ thresh\-ms
+Threshold for Shift key. If Enter is pressed within \fBthresh\-ms\fP of
+either Shift key, a Shift key release will be sent before the Enter
+keypress. This avoids the "stuck shift key" problem. Default is
+120, or 4 times the \fB\-d\fP delay if set.
+.UNINDENT
+.\" threshold in ms for shift key followed by enter (default 30 or -d * 3).
+.
+.INDENT 0.0
+.TP
 .B  \-v
 Verbose debugging mode. Prints copious trace information to \fBstderr\fP\&.
 Debugging mode is turned off when \fBmarsond\fP forks itself into the
@@ -153,11 +166,13 @@ The Enter key dropped keystroke problem happens with any SDL
 application (SDL1 or SDL2), as well as other graphics libraries. It
 happens regardless of what PS/2 keyboard you have plugged in, what
 computer you have the adaptor plugged into, or what OS that computer
-is running.
+is running. The firmware in the adaptor sends an Enter keypress, then
+8 microseconds later sends an Enter key release. There is no way to
+change this.
 .sp
 The problem where Shift/Enter causes the Shift key to act "stuck"
 happens in any application. It\(aqs particularly annoying because I\(aqm an
-inaccurate typist, and I hit Shift+Enter about 5% of the time when I\(aqm
+inaccurate typist, and I hit right Shift+Enter about 5% of the time when I\(aqm
 just trying to press Enter.
 .sp
 The specific hardware that has the problems for me is USB
@@ -213,10 +228,12 @@ the real keyboard to the virtual one. When it sees the key release
 event for the Enter key, it simply pauses for a few milliseconds
 before delivering it.
 .sp
-It also keeps track of whether the last keypress was the right Shift
-key, and when it sees an Enter keypress while right Shift is held
-down, it sends a right Shift key release event before the Enter press
-event.
+It also keeps track of the last timestamp of the left and right Shift
+keys, and if Enter is pressed too soon after Shift, it sends a key
+release for the Shift key(s). It\(aqs still possible to type Shift+Enter
+on purpose, but there must be a delay (default 120ms) between the two
+keypresses. Most people, even fast typists, won\(aqt press them that
+close together.
 .sp
 This should work with everything that uses the keyboard. It definitely
 does, with SDL 1 and 2 running under X (and SDL 1 on the console,