From 3fe494efc5eb107c4c90e96df3e6131f9960f4b9 Mon Sep 17 00:00:00 2001
From: Anton Blanchard <anton@samba.org>
Date: Tue, 13 Aug 2013 14:10:04 +1000
Subject: [PATCH] pseries: Fix stalls on hypervisor virtual console

A number of users are reporting stalls when using the pseries
hypervisor virtual console.

A simple test case is to paste 15 or 17 characters at a time
into the console. Pasting 15 characters at a time works fine
but pasting 17 characters hangs for a random amount of time.
Other activity (network, qemu monitor etc) unblocks it.

If qemu-char tries to send more than 16 characters at once,
vty_can_receive returns false. At this point we have to
wait for the guest to consume that output. Everything is good
so far.

The problem occurs when the the guest does consume the output.
We need to signal back to the qemu-char layer that we are
ready for more input. Without this we block until something
else kicks us (eg network activity).

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
(cherry picked from commit 7770b6f78a2d655e03852a5de238f5926c92be6a)

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 hw/char/spapr_vty.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/hw/char/spapr_vty.c b/hw/char/spapr_vty.c
index a799721..9c2aef8 100644
--- a/hw/char/spapr_vty.c
+++ b/hw/char/spapr_vty.c
@@ -47,6 +47,8 @@ static int vty_getchars(VIOsPAPRDevice *sdev, uint8_t *buf, int max)
         buf[n++] = dev->buf[dev->out++ % VTERM_BUFSIZE];
     }
 
+    qemu_chr_accept_input(dev->chardev);
+
     return n;
 }