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at_keyboard: Fix unreliable key presses 

This patch fixes an issue that prevented the at_keyboard module to work
(for me). The cause was a bad/wrong return value in the
grub_at_keyboard_getkey() function in grub-core/term/at_keyboard.c file
at line 237. My symptoms were to have an unresponsive keyboard. Keys
needed to be pressed 10x and more to effectively be printed sometimes
generating multiple key presses (after 1 or 2 sec of no printing). It
was very problematic when typing passphrase in early stage (with
GRUB_ENABLE_CRYPTODISK). When switched to "console" terminal input
keyboard worked perfectly. It also worked great with the GRUB 2.02
packaged by Debian (2.02+dfsg1-20). It was not an output issue but an
input one.

I've managed to analyze the issue and found that it came from the commit
216950a4e (at_keyboard: Split protocol from controller code.). Three
lines where moved from the fetch_key() function in
grub-core/term/at_keyboard.c file to the beginning of
grub_at_keyboard_getkey() function (same file). However, returning -1
made sense when it happened in fetch_key() function but not anymore in
grub_at_keyboard_getkey() function which should return GRUB_TERM_NO_KEY.
I think it was just an incomplete cut-paste missing a small manual
correction. Let's fix it.

Note: Commit message updated by Daniel Kiper.

Signed-off-by: Michael Bideau <mica.devel@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
Michael Bideau 2019-10-02 23:48:10 +02:00 committed by Daniel Kiper
parent ee4bd79ef2
commit 33203ca348
1 changed files with 1 additions and 1 deletions
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2
grub-core/term/at_keyboard.c
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@ -234,7 +234,7 @@ grub_at_keyboard_getkey (struct grub_term_input *term __attribute__ ((unused)))
return GRUB_TERM_NO_KEY;
if (! KEYBOARD_ISREADY (grub_inb (KEYBOARD_REG_STATUS)))
return -1;
return GRUB_TERM_NO_KEY;
at_key = grub_inb (KEYBOARD_REG_DATA);
old_led = ps2_state.led_status;