ctrl-x / ctrl-c may not work under GRUB2 with EFI

[Pawel Wojtalczyk <eyak@wp.pl>]

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Hello,

I run GRUB2 as 64-bit EFI application and I use gfxterm and serial as 
output.

I would like to edit commands before boot by type 'e' command. Then I 
would like to boot by press ctrl-x, but unfortunately the boot does not 
appears.

The reason is that in AMI and Phoenix BIOSes when ctrl key is pressed 
then EFI_SIMPLE_TEXT_INPUT_PROTOCOL protocol returns VT100 style 
encoding of pressed unicode character ( 
http://www.vt100.net/docs/vt100-ug/table3-5.html).

I tried to use EFI_SIMPLE_TEXT_INPUT_EX_PROTOCOL to get the pressed key 
modifier (ctrl, alt, etc), but in case when serial console redirection 
enabled in Phoenix BIOS, none characters are received via serial with 
EFI_SIMPLE_TEXT_INPUT_EX_PROTOCOL(with AMI BIOS characters are received 
in VT100 encoding style).

So maybe we can do another way. Maybe we can explicitly set key modifier 
(as in grub_terminfo_getkey() with 
http://wiki.phoenix.com/wiki/index.php/Unicode_Control_Characters 
restrictions) as following:

--- grub.orig/grub-core/term/efi/console.c      2013-07-31 
07:50:52.000000000 +0200
+++ grub/grub-core/term/efi/console.c   2013-08-06 10:28:26.117499386 +0200
@@ -125,7 +125,12 @@
      return GRUB_TERM_NO_KEY;

    if (key.scan_code == 0)
-    return key.unicode_char;
+#if defined (__i386__) || defined (__x86_64__)
+    if (key.unicode_char < 0x20 && key.unicode_char != 0 && 
key.unicode_char != '\t' && key.unicode_char != '\b' && key.unicode_char 
!= '\n' && key.unicode_char != '\r')
+      return GRUB_TERM_CTRL | (key.unicode_char - 1 + 'a');
+    else
+#endif /* defined (__i386__) || defined (__x86_64__) */
+      return key.unicode_char;
    else if (key.scan_code < ARRAY_SIZE (efi_codes))
      return efi_codes[key.scan_code];

In some remote systems EFI serial redirection must be enabled and thus 
we cannot use serial (as termianl_input) module in GRUB2 and in such 
case it would be good to allow add support for ctrl-x/ctrl-c under GRUB2 
via serial console redirection enabled in EFI and attached USB keyboard.

Regrads
Pawel Wojtalczyk

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