diff mbox

[v2] ps2: set ps/2 output buffer size as the same as kernel

Message ID 1398331907-9084-1-git-send-email-arei.gonglei@huawei.com
State New
Headers show

Commit Message

Gonglei (Arei) April 24, 2014, 9:31 a.m. UTC 
From: Gonglei <arei.gonglei@huawei.com>

According to the PS/2 Mouse/Keyboard Protocol, the keyboard outupt buffer size
is 16 bytes. And the PS2_QUEUE_SIZE 256 was introduced in Qemu from the very
beginning.

When I started a  redhat5.6 32bit guest, meanwhile tapped the keyboard as quickly as
possible, the screen would show me "i8042.c: No controller found". As a result,
I couldn't use the keyboard in the VNC client.

Previous discussion about the issue in maillist:
http://thread.gmane.org/gmane.comp.emulators.qemu/43294/focus=47180

This patch has been tested on redhat5.6 32-bit/suse11sp3 64-bit guests.
More easy meathod to reproduce:
1.boot a guest with libvirt.
2.connect to VNC client.
3.as you see the BIOS, bootloader, Linux booting, run the follow simply shell script:
for((i=0;i<10000000;i++)) do virsh send-key redhat5.6 KEY_A; done

Actual results:
dmesg show "i8042.c: No controller found." And the keyboard is out of work.

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
---
 v2: rework by Gerd Hoffmann's suggestion:
 - adjust the code style 
 - adjust the ps/2 mouse queue buffer judging condition
 - add pre_save() for ps/2 keyboard and mouse

 hw/input/ps2.c |   71 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 files changed, 67 insertions(+), 4 deletions(-)

Comments

Gerd Hoffmann April 24, 2014, 11:15 a.m. UTC | #1 
Hi,

>      if (!(s->mouse_status & MOUSE_STATUS_REMOTE) &&
> -        (s->common.queue.count < (PS2_QUEUE_SIZE - 16))) {
> +        (s->common.queue.count < PS2_QUEUE_SIZE - 4)) {
>          for(;;) {

Almost there.

The check for enougth space in the queue should be for every
ps2_mouse_send_packet() call, either by moving the check into that
function (and change return value as discussed in the other mail), or by
checking for each loop pass, for example by replacing the "for (;;)"
with "while (s->common.queue.count < PS2_QUEUE_SIZE - 4)"

Otherwise the patch looks fine now.

cheers,
  Gerd
diff mbox

Patch

diff --git a/hw/input/ps2.c b/hw/input/ps2.c
index 3412079..340ab75 100644
--- a/hw/input/ps2.c
+++ b/hw/input/ps2.c
@@ -71,10 +71,12 @@ 
 #define MOUSE_STATUS_ENABLED    0x20
 #define MOUSE_STATUS_SCALE21    0x10
 
-#define PS2_QUEUE_SIZE 256
+#define PS2_QUEUE_SIZE 16  /* Buffer size required by PS/2 protocol */
 
 typedef struct {
-    uint8_t data[PS2_QUEUE_SIZE];
+    /* Keep the data array 256 bytes long, which compatibility
+     with older qemu versions. */
+    uint8_t data[256];
     int rptr, wptr, count;
 } PS2Queue;
 
@@ -137,7 +139,7 @@  void ps2_queue(void *opaque, int b)
     PS2State *s = (PS2State *)opaque;
     PS2Queue *q = &s->queue;
 
-    if (q->count >= PS2_QUEUE_SIZE)
+    if (q->count >= PS2_QUEUE_SIZE - 1)
         return;
     q->data[q->wptr] = b;
     if (++q->wptr == PS2_QUEUE_SIZE)
@@ -375,7 +377,7 @@  static void ps2_mouse_event(void *opaque,
     }
 
     if (!(s->mouse_status & MOUSE_STATUS_REMOTE) &&
-        (s->common.queue.count < (PS2_QUEUE_SIZE - 16))) {
+        (s->common.queue.count < PS2_QUEUE_SIZE - 4)) {
         for(;;) {
             /* if not remote, send event. Multiple events are sent if
                too big deltas */
@@ -528,6 +530,34 @@  static void ps2_common_reset(PS2State *s)
     s->update_irq(s->update_arg, 0);
 }
 
+static void ps2_common_post_load(PS2State *s)
+{
+    PS2Queue *q = &s->queue;
+    int size;
+    int i;
+    int tmp_data[PS2_QUEUE_SIZE];
+
+    /* set the useful data buffer queue size, < PS2_QUEUE_SIZE */
+    size = q->count > PS2_QUEUE_SIZE ? 0 : q->count;
+
+    /* move the queue elements to the start of data array */
+    if (size > 0) {
+        for (i = 0; i < size; i++) {
+            /* move the queue elements to the temporary buffer */
+            tmp_data[i] = q->data[q->rptr];
+            if (++q->rptr == 256) {
+                q->rptr = 0;
+            }
+        }
+        memcpy(q->data, tmp_data, size);
+    }
+    /* reset rptr/wptr/count */
+    q->rptr = 0;
+    q->wptr = size;
+    q->count = size;
+    s->update_irq(s->update_arg, q->count != 0);
+}
+
 static void ps2_kbd_reset(void *opaque)
 {
     PS2KbdState *s = (PS2KbdState *) opaque;
@@ -600,18 +630,31 @@  static const VMStateDescription vmstate_ps2_keyboard_ledstate = {
 static int ps2_kbd_post_load(void* opaque, int version_id)
 {
     PS2KbdState *s = (PS2KbdState*)opaque;
+    PS2State *ps2 = &s->common;
 
     if (version_id == 2)
         s->scancode_set=2;
+
+    ps2_common_post_load(ps2);
+
     return 0;
 }
 
+static void ps2_kbd_pre_save(void *opaque)
+{
+    PS2KbdState *s = (PS2KbdState *)opaque;
+    PS2State *ps2 = &s->common;
+
+    ps2_common_post_load(ps2);
+}
+
 static const VMStateDescription vmstate_ps2_keyboard = {
     .name = "ps2kbd",
     .version_id = 3,
     .minimum_version_id = 2,
     .minimum_version_id_old = 2,
     .post_load = ps2_kbd_post_load,
+    .pre_save = ps2_kbd_pre_save,
     .fields      = (VMStateField []) {
         VMSTATE_STRUCT(common, PS2KbdState, 0, vmstate_ps2_common, PS2State),
         VMSTATE_INT32(scan_enabled, PS2KbdState),
@@ -629,11 +672,31 @@  static const VMStateDescription vmstate_ps2_keyboard = {
     }
 };
 
+static int ps2_mouse_post_load(void *opaque, int version_id)
+{
+    PS2MouseState *s = (PS2MouseState *)opaque;
+    PS2State *ps2 = &s->common;
+
+    ps2_common_post_load(ps2);
+
+    return 0;
+}
+
+static void ps2_mouse_pre_save(void *opaque)
+{
+    PS2MouseState *s = (PS2MouseState *)opaque;
+    PS2State *ps2 = &s->common;
+
+    ps2_common_post_load(ps2);
+}
+
 static const VMStateDescription vmstate_ps2_mouse = {
     .name = "ps2mouse",
     .version_id = 2,
     .minimum_version_id = 2,
     .minimum_version_id_old = 2,
+    .post_load = ps2_mouse_post_load,
+    .pre_save = ps2_mouse_pre_save,
     .fields      = (VMStateField []) {
         VMSTATE_STRUCT(common, PS2MouseState, 0, vmstate_ps2_common, PS2State),
         VMSTATE_UINT8(mouse_status, PS2MouseState),