From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59810) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bHwup-00016f-HU for qemu-devel@nongnu.org; Tue, 28 Jun 2016 13:35:16 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bHwum-0003IW-Qo for qemu-devel@nongnu.org; Tue, 28 Jun 2016 13:35:15 -0400 Received: from mail-wm0-x242.google.com ([2a00:1450:400c:c09::242]:35941) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bHwum-0003IO-KB for qemu-devel@nongnu.org; Tue, 28 Jun 2016 13:35:12 -0400 Received: by mail-wm0-x242.google.com with SMTP id c82so7692303wme.3 for ; Tue, 28 Jun 2016 10:35:12 -0700 (PDT) Received: from donizetti.lan (94-39-188-118.adsl-ull.clienti.tiscali.it. [94.39.188.118]) by smtp.gmail.com with ESMTPSA id c142sm5305wme.18.2016.06.28.10.35.10 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 28 Jun 2016 10:35:11 -0700 (PDT) Sender: Paolo Bonzini From: Paolo Bonzini Date: Tue, 28 Jun 2016 19:34:00 +0200 Message-Id: <1467135242-874-31-git-send-email-pbonzini@redhat.com> In-Reply-To: <1467135242-874-1-git-send-email-pbonzini@redhat.com> References: <1467135242-874-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PULL 30/32] serial: reinstate watch after migration List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Otherwise, a serial port can get stuck if it is migrated while flow control is in effect. Tested-by: Bret Ketchum Reviewed-by: Dr. David Alan Gilbert Signed-off-by: Paolo Bonzini --- hw/char/serial.c | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) diff --git a/hw/char/serial.c b/hw/char/serial.c index af39e8f..3442f47 100644 --- a/hw/char/serial.c +++ b/hw/char/serial.c @@ -644,8 +644,29 @@ static int serial_post_load(void *opaque, int version_id) if (s->thr_ipending == -1) { s->thr_ipending = ((s->iir & UART_IIR_ID) == UART_IIR_THRI); } - if (s->tsr_retry > MAX_XMIT_RETRY) { - s->tsr_retry = MAX_XMIT_RETRY; + + if (s->tsr_retry > 0) { + /* tsr_retry > 0 implies LSR.TEMT = 0 (transmitter not empty). */ + if (s->lsr & UART_LSR_TEMT) { + error_report("inconsistent state in serial device " + "(tsr empty, tsr_retry=%d", s->tsr_retry); + return -1; + } + + if (s->tsr_retry > MAX_XMIT_RETRY) { + s->tsr_retry = MAX_XMIT_RETRY; + } + + assert(s->watch_tag == 0); + s->watch_tag = qemu_chr_fe_add_watch(s->chr, G_IO_OUT|G_IO_HUP, + serial_watch_cb, s); + } else { + /* tsr_retry == 0 implies LSR.TEMT = 1 (transmitter empty). */ + if (!(s->lsr & UART_LSR_TEMT)) { + error_report("inconsistent state in serial device " + "(tsr not empty, tsr_retry=0"); + return -1; + } } s->last_break_enable = (s->lcr >> 6) & 1; -- 2.7.4