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I apologize if this message sounds exasperated.  I spent the entire evening porting my game from GLFW to SDL 2.0, only to find out that it does not accept my keyboard layout.  Like many other Linux users, I've used xmodmap to remap a few keys on my keyboard (home/page down and end/page up, specifically).  However, when trying to run my SDL app, it says

Keyboard layout unknown, please send the following to the SDL mailing list:

<rest of message at end of email>


and when I press any other key, it usually says something like

The key you just pressed is not recognized by SDL. To help get this fixed, please report this to the SDL mailing list X11 KeyCode 38 (30), X11 KeySym 0x61 (a).


and the key does nothing.  I was quite surprised by this, especially since remapping only four keys causes SDL to choke on the other keys, and since every other game support library has no problem with my keyboard settings.  Removing my xmodmap bindings makes SDL happy, but that is not a solution to the problem, because it may still cause trouble for my game's userbase.  If there is not a good solution, I'll have to give up on using SDL, which is a shame because until now it seemed to have the best combination of configurability and portability.


The entire message SDL prints on initialization is as follows:

Keyboard layout unknown, please send the following to the SDL mailing list:
code = 1, sym = 0xFF1B (Escape) scancode = 41 (Escape)
code = 2, sym = 0x31 (1) scancode = 40 (Return)
code = 3, sym = 0x32 (2) scancode = 41 (Escape)
code = 4, sym = 0x33 (3) scancode = 42 (Backspace)
code = 5, sym = 0x34 (4) scancode = 43 (Tab)
code = 6, sym = 0x35 (5) scancode = 44 (Space)
code = 7, sym = 0x36 (6) scancode = 45 (-)
code = 8, sym = 0x37 (7) scancode = 46 (=)
code = 9, sym = 0x38 ( scancode = 47 ([)
code = 10, sym = 0x39 (9) scancode = 48 (])
code = 11, sym = 0x30 (0) scancode = 39 (0)
code = 12, sym = 0x2D (minus) scancode not found
code = 13, sym = 0x3D (equal) scancode not found
code = 14, sym = 0xFF08 (BackSpace) scancode = 42 (Backspace)
code = 15, sym = 0xFF09 (Tab) scancode = 43 (Tab)
code = 16, sym = 0x71 (q) scancode not found
code = 17, sym = 0x77 (w) scancode not found
code = 18, sym = 0x65 (e) scancode not found
code = 19, sym = 0x72 (r) scancode not found
code = 20, sym = 0x74 (t) scancode not found
code = 21, sym = 0x79 (y) scancode not found
code = 22, sym = 0x75 (u) scancode not found
code = 23, sym = 0x69 (i) scancode not found
code = 24, sym = 0x6F (o) scancode not found
code = 25, sym = 0x70 (p) scancode not found
code = 26, sym = 0x5B (bracketleft) scancode not found
code = 27, sym = 0x5D (bracketright) scancode not found
code = 28, sym = 0xFF0D (Return) scancode = 40 (Return)
code = 29, sym = 0xFFE3 (Control_L) scancode = 224 (Left Ctrl)
code = 30, sym = 0x61 (a) scancode not found
code = 31, sym = 0x73 (s) scancode not found
code = 32, sym = 0x64 (d) scancode not found
code = 33, sym = 0x66 (f) scancode not found
code = 34, sym = 0x67 (g) scancode not found
code = 35, sym = 0x68 (h) scancode not found
code = 36, sym = 0x6A (j) scancode not found
code = 37, sym = 0x6B (k) scancode not found
code = 38, sym = 0x6C (l) scancode not found
code = 39, sym = 0x3B (semicolon) scancode not found
code = 40, sym = 0x27 (apostrophe) scancode not found
code = 41, sym = 0x60 (grave) scancode not found
code = 42, sym = 0xFFE1 (Shift_L) scancode = 225 (Left Shift)
code = 43, sym = 0x5C (backslash) scancode not found
code = 44, sym = 0x7A (z) scancode not found
code = 45, sym = 0x78 (x) scancode not found
code = 46, sym = 0x63 (c) scancode not found
code = 47, sym = 0x76 (v) scancode not found
code = 48, sym = 0x62 (b) scancode not found
code = 49, sym = 0x6E (n) scancode not found
code = 50, sym = 0x6D (m) scancode not found
code = 51, sym = 0x2C (comma) scancode not found
code = 52, sym = 0x2E (period) scancode not found
code = 53, sym = 0x2F (slash) scancode not found
code = 54, sym = 0xFFE2 (Shift_R) scancode = 229 (Right Shift)
code = 55, sym = 0xFFAA (KP_Multiply) scancode = 85 (Keypad *)
code = 56, sym = 0xFFE9 (Alt_L) scancode = 226 (Left Alt)
code = 57, sym = 0x20 (space) scancode not found
code = 58, sym = 0xFFEB (Super_L) scancode = 227 (Left GUI)
code = 59, sym = 0xFFBE (F1) scancode = 58 (F1)
code = 60, sym = 0xFFBF (F2) scancode = 59 (F2)
code = 61, sym = 0xFFC0 (F3) scancode = 60 (F3)
code = 62, sym = 0xFFC1 (F4) scancode = 61 (F4)
code = 63, sym = 0xFFC2 (F5) scancode = 62 (F5)
code = 64, sym = 0xFFC3 (F6) scancode = 63 (F6)
code = 65, sym = 0xFFC4 (F7) scancode = 64 (F7)
code = 66, sym = 0xFFC5 (F scancode = 65 (F
code = 67, sym = 0xFFC6 (F9) scancode = 66 (F9)
code = 68, sym = 0xFFC7 (F10) scancode = 67 (F10)
code = 69, sym = 0xFF7F (Num_Lock) scancode = 83 (Numlock)
code = 70, sym = 0xFF14 (Scroll_Lock) scancode = 71 (ScrollLock)
code = 71, sym = 0xFF95 (KP_Home) scancode = 95 (Keypad 7)
code = 72, sym = 0xFF97 (KP_Up) scancode = 96 (Keypad
code = 73, sym = 0xFF9A (KP_Prior) scancode = 97 (Keypad 9)
code = 74, sym = 0xFFAD (KP_Subtract) scancode = 86 (Keypad -)
code = 75, sym = 0xFF96 (KP_Left) scancode = 92 (Keypad 4)
code = 76, sym = 0xFF9D (KP_Begin) scancode = 93 (Keypad 5)
code = 77, sym = 0xFF98 (KP_Right) scancode = 94 (Keypad 6)
code = 78, sym = 0xFFAB (KP_Add) scancode = 87 (Keypad +)
code = 79, sym = 0xFF9C (KP_End) scancode = 89 (Keypad 1)
code = 80, sym = 0xFF99 (KP_Down) scancode = 90 (Keypad 2)
code = 81, sym = 0xFF9B (KP_Next) scancode = 91 (Keypad 3)
code = 82, sym = 0xFF9E (KP_Insert) scancode = 98 (Keypad 0)
code = 83, sym = 0xFF9F (KP_Delete) scancode = 99 (Keypad .)
code = 84, sym = 0xFE03 (ISO_Level3_Shift) scancode not found
code = 86, sym = 0x3C (less) scancode not found
code = 87, sym = 0xFFC8 (F11) scancode = 68 (F11)
code = 88, sym = 0xFFC9 (F12) scancode = 69 (F12)
code = 90, sym = 0xFF26 (Katakana) scancode not found
code = 91, sym = 0xFF25 (Hiragana) scancode not found
code = 92, sym = 0xFF23 (Henkan_Mode) scancode not found
code = 93, sym = 0xFF27 (Hiragana_Katakana) scancode not found
code = 94, sym = 0xFF22 (Muhenkan) scancode not found
code = 96, sym = 0xFF8D (KP_Enter) scancode = 88 (Keypad Enter)
code = 97, sym = 0xFFE4 (Control_R) scancode = 228 (Right Ctrl)
code = 98, sym = 0xFFAF (KP_Divide) scancode = 84 (Keypad /)
code = 99, sym = 0xFF20 (Multi_key) scancode not found
code = 100, sym = 0xFFEA (Alt_R) scancode = 230 (Right Alt)
code = 101, sym = 0xFF0A (Linefeed) scancode not found
code = 102, sym = 0xFF55 (Prior) scancode = 75 (PageUp)
code = 103, sym = 0xFF52 (Up) scancode = 82 (Up)
code = 104, sym = 0xFF50 (Home) scancode = 74 (Home)
code = 105, sym = 0xFF51 (Left) scancode = 80 (Left)
code = 106, sym = 0xFF53 (Right) scancode = 79 (Right)
code = 107, sym = 0xFF56 (Next) scancode = 78 (PageDown)
code = 108, sym = 0xFF54 (Down) scancode = 81 (Down)
code = 109, sym = 0xFF57 (End) scancode = 77 (End)
code = 110, sym = 0xFF63 (Insert) scancode = 73 (Insert)
code = 111, sym = 0xFFFF (Delete) scancode = 76 (Delete)
code = 113, sym = 0x1008FF12 (XF86AudioMute) scancode not found
code = 114, sym = 0x1008FF11 (XF86AudioLowerVolume) scancode not found
code = 115, sym = 0x1008FF13 (XF86AudioRaiseVolume) scancode not found
code = 116, sym = 0x1008FF2A (XF86PowerOff) scancode not found
code = 117, sym = 0xFFBD (KP_Equal) scancode = 103 (Keypad =)
code = 118, sym = 0xB1 (plusminus) scancode not found
code = 119, sym = 0xFF13 (Pause) scancode = 72 (Pause)
code = 120, sym = 0x1008FF4A (XF86LaunchA) scancode not found
code = 121, sym = 0xFFAE (KP_Decimal) scancode = 99 (Keypad .)
code = 122, sym = 0xFF31 (Hangul) scancode not found
code = 123, sym = 0xFF34 (Hangul_Hanja) scancode not found
code = 125, sym = 0xFFEB (Super_L) scancode = 227 (Left GUI)
code = 126, sym = 0xFFEC (Super_R) scancode = 231 (Right GUI)
code = 127, sym = 0xFF67 (Menu) scancode = 118 (Menu)
code = 128, sym = 0xFF69 (Cancel) scancode = 120 (Stop)
code = 129, sym = 0xFF66 (Redo) scancode = 121 (Again)
code = 130, sym = 0x1005FF70 (SunProps) scancode not found
code = 131, sym = 0xFF65 (Undo) scancode = 122 (Undo)
code = 132, sym = 0x1005FF71 (SunFront) scancode not found
code = 133, sym = 0x1008FF57 (XF86Copy) scancode not found
code = 134, sym = 0x1005FF73 (SunOpen) scancode not found
code = 135, sym = 0x1008FF6D (XF86Paste) scancode not found
code = 136, sym = 0xFF68 (Find) scancode = 126 (Find)
code = 137, sym = 0x1008FF58 (XF86Cut) scancode not found
code = 138, sym = 0xFF6A (Help) scancode = 117 (Help)
code = 139, sym = 0x1008FF65 (XF86MenuKB) scancode not found
code = 140, sym = 0x1008FF1D (XF86Calculator) scancode not found
code = 142, sym = 0x1008FF2F (XF86Sleep) scancode not found
code = 143, sym = 0x1008FF2B (XF86WakeUp) scancode not found
code = 144, sym = 0x1008FF5D (XF86Explorer) scancode not found
code = 145, sym = 0x1008FF7B (XF86Send) scancode not found
code = 147, sym = 0x1008FF8A (XF86Xfer) scancode not found
code = 148, sym = 0x1008FF41 (XF86Launch1) scancode not found
code = 149, sym = 0x1008FF42 (XF86Launch2) scancode not found
code = 150, sym = 0x1008FF2E (XF86WWW) scancode not found
code = 151, sym = 0x1008FF5A (XF86DOS) scancode not found
code = 152, sym = 0x1008FF2D (XF86ScreenSaver) scancode not found
code = 154, sym = 0x1008FF74 (XF86RotateWindows) scancode not found
code = 155, sym = 0x1008FF19 (XF86Mail) scancode not found
code = 156, sym = 0x1008FF30 (XF86Favorites) scancode not found
code = 157, sym = 0x1008FF33 (XF86MyComputer) scancode not found
code = 158, sym = 0x1008FF26 (XF86Back) scancode not found
code = 159, sym = 0x1008FF27 (XF86Forward) scancode not found
code = 161, sym = 0x1008FF2C (XF86Eject) scancode not found
code = 162, sym = 0x1008FF2C (XF86Eject) scancode not found
code = 163, sym = 0x1008FF17 (XF86AudioNext) scancode not found
code = 164, sym = 0x1008FF14 (XF86AudioPlay) scancode not found
code = 165, sym = 0x1008FF16 (XF86AudioPrev) scancode not found
code = 166, sym = 0x1008FF15 (XF86AudioStop) scancode not found
code = 167, sym = 0x1008FF1C (XF86AudioRecord) scancode not found
code = 168, sym = 0x1008FF3E (XF86AudioRewind) scancode not found
code = 169, sym = 0x1008FF6E (XF86Phone) scancode not found
code = 171, sym = 0x1008FF81 (XF86Tools) scancode not found
code = 172, sym = 0x1008FF18 (XF86HomePage) scancode not found
code = 173, sym = 0x1008FF73 (XF86Reload) scancode not found
code = 174, sym = 0x1008FF56 (XF86Close) scancode not found
code = 177, sym = 0x1008FF78 (XF86ScrollUp) scancode not found
code = 178, sym = 0x1008FF79 (XF86ScrollDown) scancode not found
code = 179, sym = 0x28 (parenleft) scancode not found
code = 180, sym = 0x29 (parenright) scancode not found
code = 181, sym = 0x1008FF68 (XF86New) scancode not found
code = 182, sym = 0xFF66 (Redo) scancode = 121 (Again)
code = 183, sym = 0x1008FF81 (XF86Tools) scancode not found
code = 184, sym = 0x1008FF45 (XF86Launch5) scancode not found
code = 185, sym = 0x1008FF46 (XF86Launch6) scancode not found
code = 186, sym = 0x1008FF47 (XF86Launch7) scancode not found
code = 187, sym = 0x1008FF48 (XF86Launch8) scancode not found
code = 188, sym = 0x1008FF49 (XF86Launch9) scancode not found
code = 191, sym = 0x1008FFA9 (XF86TouchpadToggle) scancode not found
code = 192, sym = 0x1008FFB0 (XF86TouchpadOn) scancode not found
code = 193, sym = 0x1008FFB1 (XF86TouchpadOff) scancode not found
code = 195, sym = 0xFF7E (Mode_switch) scancode = 257 (ModeSwitch)
code = 200, sym = 0x1008FF14 (XF86AudioPlay) scancode not found
code = 201, sym = 0x1008FF31 (XF86AudioPause) scancode not found
code = 202, sym = 0x1008FF43 (XF86Launch3) scancode not found
code = 203, sym = 0x1008FF44 (XF86Launch4) scancode not found
code = 204, sym = 0x1008FF4B (XF86LaunchB) scancode not found
code = 205, sym = 0x1008FFA7 (XF86Suspend) scancode not found
code = 206, sym = 0x1008FF56 (XF86Close) scancode not found
code = 207, sym = 0x1008FF14 (XF86AudioPlay) scancode not found
code = 208, sym = 0x1008FF97 (XF86AudioForward) scancode not found
code = 210, sym = 0xFF61 (Print) scancode = 70 (PrintScreen)
code = 212, sym = 0x1008FF8F (XF86WebCam) scancode not found
code = 215, sym = 0x1008FF19 (XF86Mail) scancode not found
code = 216, sym = 0x1008FF8E (XF86Messenger) scancode not found
code = 217, sym = 0x1008FF1B (XF86Search) scancode not found
code = 218, sym = 0x1008FF5F (XF86Go) scancode not found
code = 219, sym = 0x1008FF3C (XF86Finance) scancode not found
code = 220, sym = 0x1008FF5E (XF86Game) scancode not found
code = 221, sym = 0x1008FF36 (XF86Shop) scancode not found
code = 223, sym = 0xFF69 (Cancel) scancode = 120 (Stop)
code = 224, sym = 0x1008FF03 (XF86MonBrightnessDown) scancode not found
code = 225, sym = 0x1008FF02 (XF86MonBrightnessUp) scancode not found
code = 226, sym = 0x1008FF32 (XF86AudioMedia) scancode not found
code = 227, sym = 0x1008FF59 (XF86Display) scancode not found
code = 228, sym = 0x1008FF04 (XF86KbdLightOnOff) scancode not found
code = 229, sym = 0x1008FF06 (XF86KbdBrightnessDown) scancode not found
code = 230, sym = 0x1008FF05 (XF86KbdBrightnessUp) scancode not found
code = 231, sym = 0x1008FF7B (XF86Send) scancode not found
code = 232, sym = 0x1008FF72 (XF86Reply) scancode not found
code = 233, sym = 0x1008FF90 (XF86MailForward) scancode not found
code = 234, sym = 0x1008FF77 (XF86Save) scancode not found
code = 235, sym = 0x1008FF5B (XF86Documents) scancode not found
code = 236, sym = 0x1008FF93 (XF86Battery) scancode not found
code = 237, sym = 0x1008FF94 (XF86Bluetooth) scancode not found
code = 238, sym = 0x1008FF95 (XF86WLAN) scancode not found

I investigated the source code on my own and found out that src/video/x11/SDL_x11keyboard.c is detecting the OSs scancode table through use of a fingerprint which contains (home, page up, page down), which are 3 of the 4 keys I have remapped.  To allow SDL to deal gracefully with this, I expanded the fingerprint to (home, page up, up, left, delete, KP enter), with an extra condition that only four of the six entries must be correct for it to decide on the scancode table.  This should make it so that people who have remapped only a few keys will still be able to use SDL-based games.


I would love to help out, but I am not familiar with the patch request/code review process for this codebase.  I've tentatively attached a patch file to this email, but if there is a better way for me to submit this, please let me know.  Sorry for the trouble.


On Wed, Mar 19, 2014 at 12:45 AM, Lewis Wall wrote:

Typically people enter bugs at http://bugzilla.libsdl.org and attach patches so they don't get lost on the e-mail list.

I got your patch in though, thanks!
https://hg.libsdl.org/SDL/rev/fb44c438a3e5




On Sat, Mar 22, 2014 at 8:37 PM, Lewis Wall wrote:

Thanks.  I'll remember that for next time.



On Sun, Mar 23, 2014 at 9:45 AM, Sam Lantinga wrote:

I've run into this problem too.


The patch still seems like a flaky/brittle solution.  Does anyone know of a better method for X11 layout detection?


Jonny D

IIRC, the XInput2 extension reports raw key events, before being processed by the server. [1] I haven't verified this, but it might be possible to obtain key codes before layout mapping on the server, avoiding the layout detection hack entirely.


That said, I wouldn't be surprised if layout-independent scancodes turn out impossible to implement through X11. In that case, the current hack is pretty much the best it can get.


[1] http://who-t.blogspot.ch/2009/07/xi2-recipes-part-4.html




2014-03-23 21:02 GMT+01:00 Jonathan Dearborn: