diff mbox

[PULL,3/3] input: Add trace event for empty keyboard queue

Message ID 20170504055040.31904-4-kraxel@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Gerd Hoffmann May 4, 2017, 5:50 a.m. UTC 
From: Alexander Graf <agraf@suse.de>

When driving QEMU from the outside, we have basically no chance to
determine how quickly the guest OS picks up key events, so we usually
have to limit ourselves to very slow keyboard presses to make sure
the guest always has enough chance to pick them up.

This patch adds a trace events when the keyboarde queue is drained.
An external driver can use that as hint that new keys can be pressed.

Signed-off-by: Alexander Graf <agraf@suse.de>
Message-id: 1490883775-94658-1-git-send-email-agraf@suse.de
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/input/hid.c        | 4 ++++
 hw/input/trace-events | 1 +
 2 files changed, 5 insertions(+)
diff mbox

Patch

diff --git a/hw/input/hid.c b/hw/input/hid.c
index fa9cc4c616..93887ecc43 100644
--- a/hw/input/hid.c
+++ b/hw/input/hid.c
@@ -256,6 +256,10 @@  static void hid_keyboard_process_keycode(HIDState *hs)
     slot = hs->head & QUEUE_MASK; QUEUE_INCR(hs->head); hs->n--;
     keycode = hs->kbd.keycodes[slot];
 
+    if (!hs->n) {
+        trace_hid_kbd_queue_empty();
+    }
+
     key = keycode & 0x7f;
     index = key | ((hs->kbd.modifiers & (1 << 8)) >> 1);
     hid_code = hid_usage_keys[index];
diff --git a/hw/input/trace-events b/hw/input/trace-events
index f3bfbede5c..5a87818b49 100644
--- a/hw/input/trace-events
+++ b/hw/input/trace-events
@@ -24,6 +24,7 @@  milkymist_softusb_pulse_irq(void) "Pulse IRQ"
 
 # hw/input/hid.c
 hid_kbd_queue_full(void) "queue full"
+hid_kbd_queue_empty(void) "queue empty"
 
 # hw/input/virtio
 virtio_input_queue_full(void) "queue full"