From ad91e3776808507cbef9e6d758b89d7ca92a4c7e Mon Sep 17 00:00:00 2001
From: Wez Furlong <wez@wezfurlong.org>
Date: Wed, 6 Apr 2022 20:44:53 -0700
Subject: [PATCH] Secondary DA response -> vt220, version 277

This persuades vim to set ttymouse=sgr by default.
We're carefully sitting below 279 which triggers
some queries for things that we don't respond to yet.

refs: https://github.com/wez/wezterm/issues/1825
---
 docs/changelog.md             |  1 +
 term/src/terminalstate/mod.rs | 13 ++++++++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/docs/changelog.md b/docs/changelog.md
index e37aac979..5ef6849db 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -25,6 +25,7 @@ As features stabilize some brief notes about them will accumulate here.
 * Color schemes: [Retro](colorschemes/r/index.md#retro), [GitHub Dark](colorschemes/g/index.md#github-dark), [Blazer](colorschemes/b/index.md#blazer)
 * Wayland: touchpad scroll is now more responsive/precise. Thanks to [@davidrios](https://github.com/davidrios)! [#1800](https://github.com/wez/wezterm/pull/1800)
 * Kitty image protocol: now also supports shared memory data transmission. Thanks to [@tantei3](https://github.com/tantei3)! [#1810](https://github.com/wez/wezterm/pull/1810)
+* Secondary DA response bumped up to persuade vim to set `ttymouse=sgr` by default. [#1825](https://github.com/wez/wezterm/issues/1825)
 
 #### Fixed
 * Incorrect csi-u encoding with non-ascii characters. [#1746](https://github.com/wez/wezterm/issues/1746)
diff --git a/term/src/terminalstate/mod.rs b/term/src/terminalstate/mod.rs
index 1b8bef0d7..1d9098132 100644
--- a/term/src/terminalstate/mod.rs
+++ b/term/src/terminalstate/mod.rs
@@ -1204,7 +1204,18 @@ impl TerminalState {
                 self.writer.flush().ok();
             }
             Device::RequestSecondaryDeviceAttributes => {
-                self.writer.write(b"\x1b[>0;0;0c").ok();
+                // Response is: Pp ; Pv ; Pc
+                // Where Pp=1 means vt220
+                // and Pv is the firmware version.
+                // Pc is always 0.
+                // Because our default TERM is xterm, the firmware
+                // version will be considered to be equialent to xterm's
+                // patch levels, with the following effects:
+                // pv < 95 -> ttymouse=xterm
+                // pv >= 95 < 277 -> ttymouse=xterm2
+                // pv >= 277 -> ttymouse=sgr
+                // pv >= 279 - xterm will probe for additional device settings.
+                self.writer.write(b"\x1b[>1;277;0c").ok();
                 self.writer.flush().ok();
             }
             Device::RequestTertiaryDeviceAttributes => {