From: Gonglei <arei.gong...@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.gong...@huawei.com> --- hw/input/ps2.c | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff --git a/hw/input/ps2.c b/hw/input/ps2.c index 3412079..a754fef 100644 --- a/hw/input/ps2.c +++ b/hw/input/ps2.c @@ -71,7 +71,7 @@ #define MOUSE_STATUS_ENABLED 0x20 #define MOUSE_STATUS_SCALE21 0x10 -#define PS2_QUEUE_SIZE 256 +#define PS2_QUEUE_SIZE 16 /* Keyboard output buffer size */ typedef struct { uint8_t data[PS2_QUEUE_SIZE]; @@ -137,7 +137,7 @@ 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 +375,7 @@ 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)) { for(;;) { /* if not remote, send event. Multiple events are sent if too big deltas */ -- 1.6.0.2
