DT8: clarify why "QUERY ACTUAL LEVEL" is needed

jktjkt · sde1000 · commit 95eac0a4d538 · 2024-08-02T19:36:23.000+01:00
I was wondering why the code was sending a seemingly useless command,
but it turns out that this is explicitly mandated by a note in the
standard. Let's put that into a comment.
diff --git a/dali/gear/sequences.py b/dali/gear/sequences.py
@@ -69,6 +69,7 @@ def QueryDT8ColourValue(
             "'query' must be a value from QueryColourValueDTR enumerator"
         )
 
+    # 62386-209, command 250, Note 2: start by sending "QUERY ACTUAL LEVEL"
     yield QueryActualLevel(address)
     yield DTR0(query.value)
     msb = yield QueryColourValue(address)

Original file line number	Diff line number	Diff line change
`@@ -69,6 +69,7 @@ def QueryDT8ColourValue(`
`69`	`69`	`"'query' must be a value from QueryColourValueDTR enumerator"`
`70`	`70`	`)`
`71`	`71`
	`72`	`+ # 62386-209, command 250, Note 2: start by sending "QUERY ACTUAL LEVEL"`
`72`	`73`	`yield QueryActualLevel(address)`
`73`	`74`	`yield DTR0(query.value)`
`74`	`75`	`msb = yield QueryColourValue(address)`