[Qemu-devel] [PATCH v3] ps2: fix sending of PAUSE/BREAK scancodes

["Daniel P. Berrange" <berrange@redhat.com>]

The processing of the scancodes for PAUSE/BREAK  has been broken since
the conversion to qcodes in:

  commit 8c10e0baf0260b59a4e984744462a18016662e3e
  Author: Hervé Poussineau <hpoussin@reactos.org>
  Date:   Thu Sep 15 22:06:26 2016 +0200

    ps2: use QEMU qcodes instead of scancodes

When using a VNC client, with the raw scancode extension, the client
will send a scancode of 0xc6 for both PAUSE and BREAK. There is mistakenly
no entry in the qcode_to_number table for this scancode, so
ps2_keyboard_event() just generates a log message and discards the
scancode

When using a SPICE client, it will also send 0xc6 for BREAK, but
will send 0xe1 0x1d 0x45 0xe1 0x9d 0xc5 for PAUSE. There is no
entry in the qcode_to_number table for the scancode 0xe1 because
it is a special XT keyboard prefix not mapping to any QKeyCode.
Again ps2_keyboard_event() just generates a log message and discards
the scancode. The following 0x1d, 0x45, 0x9d, 0xc5 scancodes get
handled correctly. Rather than trying to handle 3 byte sequences
of scancodes in the PS/2 driver, special case the SPICE input
code so that it captures the 3 byte pause sequence and turns it
into a Pause QKeyCode.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---

Changed in v3:

 - Treat entire '0xe1 0x1d 0x45 0xe1 0x9d 0xc5' as make code,
   there is no break code for PAUSE.

 ui/input-keymap.c |  1 +
 ui/spice-input.c  | 14 ++++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/ui/input-keymap.c b/ui/input-keymap.c
index 8a1476fc48..9211f835be 100644
--- a/ui/input-keymap.c
+++ b/ui/input-keymap.c
@@ -98,6 +98,7 @@ static const int qcode_to_number[] = {
     [Q_KEY_CODE_KP_ENTER] = 0x9c,
     [Q_KEY_CODE_KP_DECIMAL] = 0x53,
     [Q_KEY_CODE_SYSRQ] = 0x54,
+    [Q_KEY_CODE_PAUSE] = 0xc6,
 
     [Q_KEY_CODE_KP_0] = 0x52,
     [Q_KEY_CODE_KP_1] = 0x4f,
diff --git a/ui/spice-input.c b/ui/spice-input.c
index 918580239d..3d41aa1831 100644
--- a/ui/spice-input.c
+++ b/ui/spice-input.c
@@ -32,6 +32,7 @@ typedef struct QemuSpiceKbd {
     SpiceKbdInstance sin;
     int ledstate;
     bool emul0;
+    size_t pauseseq;
 } QemuSpiceKbd;
 
 static void kbd_push_key(SpiceKbdInstance *sin, uint8_t frag);
@@ -49,6 +50,7 @@ static const SpiceKbdInterface kbd_interface = {
 
 static void kbd_push_key(SpiceKbdInstance *sin, uint8_t scancode)
 {
+    static const uint8_t pauseseq[] = { 0xe1, 0x1d, 0x45, 0xe1, 0x9d, 0xc5 };
     QemuSpiceKbd *kbd = container_of(sin, QemuSpiceKbd, sin);
     int keycode;
     bool up;
@@ -57,6 +59,18 @@ static void kbd_push_key(SpiceKbdInstance *sin, uint8_t scancode)
         kbd->emul0 = true;
         return;
     }
+
+    if (scancode == pauseseq[kbd->pauseseq]) {
+        kbd->pauseseq++;
+        if (kbd->pauseseq == G_N_ELEMENTS(pauseseq)) {
+            qemu_input_event_send_key_qcode(NULL, Q_KEY_CODE_PAUSE, true);
+            kbd->pauseseq = 0;
+        }
+        return;
+    } else {
+        kbd->pauseseq = 0;
+    }
+
     keycode = scancode & ~SCANCODE_UP;
     up = scancode & SCANCODE_UP;
     if (kbd->emul0) {
-- 
2.13.3