[PATCH 1/1] efi_loader: escape key handling

[Heinrich Schuchardt]

Up to now the escape key was not correctly detected in UEFI applications.
We had to hit it twice for a single escape to be recognized.

Use a 10 ms delay to detect if we are dealing with the escape key or an
escape sequence.

Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
---
 lib/efi_loader/efi_console.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/lib/efi_loader/efi_console.c b/lib/efi_loader/efi_console.c
index 011accab78..705109596e 100644
--- a/lib/efi_loader/efi_console.c
+++ b/lib/efi_loader/efi_console.c
@@ -14,6 +14,7 @@
 #include <env.h>
 #include <stdio_dev.h>
 #include <video_console.h>
+#include <linux/delay.h>

 #define EFI_COUT_MODE_2 2
 #define EFI_MAX_COUT_MODE 3
@@ -688,6 +689,17 @@ static efi_status_t efi_cin_read_key(struct efi_key_data *key)

 	switch (ch) {
 	case 0x1b:
+		/*
+		 * If a second key is received within 10 ms, assume that we are
+		 * dealing with an escape sequence. Otherwise consider this the
+		 * escape key being hit. 10 ms is long enough to work fine at
+		 * 1200 baud and above.
+		 */
+		udelay(10000);
+		if (!tstc()) {
+			pressed_key.scan_code = 23;
+			break;
+		}
 		/*
 		 * Xterm Control Sequences
 		 * https://www.xfree86.org/4.8.0/ctlseqs.html
--
2.29.2