[Qemu-devel] Bug in SDL key event processing

[Tomas Carnecky <tom@dbservice.com>]

I just spend half day figuring out why my arrow keys and some other keys 
wouldn't work inside of the guest OS. Turns out you have a capital error 
in your SDL keyboard event parsing code.

Once the event hits sdl_process_key(), the function converts the event 
to a keycode. That depends on whether a keyboard layout has been loaded 
(-k en-us) or not. If not, it calls into sdl_keyevent_to_keycode() which 
  uses the SDL keyboard event scancode (presumably the X11 keycode) and 
converts it to keycodes that are then sent to the guest OS. The problem 
is that you assume a fixed layout of the X11 'scancodes', and use a 
table (x_keycode_to_pc_keycode) to convert those. Well, my xserver 
generates keycode=111 for the 'Up' key, which then your code translated 
to 'Print'. I tried changing the keymap files, but it didn't make any 
difference since qemu doesn't use those if no layout has been selected 
using the '-k' switch. If I load the en-use keymap, all keys work as 
expected.

Why is there OS (X11/Windows) specific code in the SDL frontend? And why 
does qemu need keymaps anyway? I would expect qemu to translate my 
keypresses to corresponding bios scancodes and do no further processing. 
  If you do that, you won't need the keymaps code, just a table to 
translate from SDL events to bios scancodes. For that you'd need just 
one table, holding ~322 elements. That's how many keysyms are defined in 
SDL.

tom