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authorLinus Torvalds <torvalds@linux-foundation.org>2026-09-20 08:15:23 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-09-20 08:15:23 -0700
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tree0446500af9a76d4e8b2a72a0a41391ceede73a10 /Documentation/admin-guide/lcd-panel-cgram.rst
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Merge tag 'locking-urgent-2026-09-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipgrafted
Pull futex fix from Ingo Molnar: - Also allocate a default private futex hash on vfork() as well, to avoid races with (private) futex waiters (Peter Zijlstra) * tag 'locking-urgent-2026-09-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: futex: Also allocate private hash on vfork()
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+======================================
+Parallel port LCD/Keypad Panel support
+======================================
+
+Some LCDs allow you to define up to 8 characters, mapped to ASCII
+characters 0 to 7. The escape code to define a new character is
+'\e[LG' followed by one digit from 0 to 7, representing the character
+number, and up to 8 couples of hex digits terminated by a semi-colon
+(';'). Each couple of digits represents a line, with 1-bits for each
+illuminated pixel with LSB on the right. Lines are numbered from the
+top of the character to the bottom. On a 5x7 matrix, only the 5 lower
+bits of the 7 first bytes are used for each character. If the string
+is incomplete, only complete lines will be redefined. Here are some
+examples::
+
+ printf "\e[LG0010101050D1F0C04;" => 0 = [enter]
+ printf "\e[LG1040E1F0000000000;" => 1 = [up]
+ printf "\e[LG2000000001F0E0400;" => 2 = [down]
+ printf "\e[LG3040E1F001F0E0400;" => 3 = [up-down]
+ printf "\e[LG40002060E1E0E0602;" => 4 = [left]
+ printf "\e[LG500080C0E0F0E0C08;" => 5 = [right]
+ printf "\e[LG60016051516141400;" => 6 = "IP"
+
+ printf "\e[LG00103071F1F070301;" => big speaker
+ printf "\e[LG00002061E1E060200;" => small speaker
+
+Willy