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[Qemu-devel] [PATCH v2 6/6] serial: reinstate watch after migration
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH v2 6/6] serial: reinstate watch after migration |
Date: |
Thu, 23 Jun 2016 19:22:19 +0200 |
Otherwise, a serial port can get stuck if it is migrated while flow control
is in effect.
Tested-by: Bret Ketchum <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
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;
--
2.5.5
- [Qemu-devel] [PATCH v2 0/6] serial: flow control fixes, Paolo Bonzini, 2016/06/23
- [Qemu-devel] [PATCH v2 1/6] serial: make tsr_retry unsigned, Paolo Bonzini, 2016/06/23
- [Qemu-devel] [PATCH v2 5/6] serial: remove watch on reset, Paolo Bonzini, 2016/06/23
- [Qemu-devel] [PATCH v2 4/6] char: change qemu_chr_fe_add_watch to return unsigned, Paolo Bonzini, 2016/06/23
- [Qemu-devel] [PATCH v2 2/6] serial: simplify tsr_retry reset, Paolo Bonzini, 2016/06/23
- [Qemu-devel] [PATCH v2 3/6] serial: separate serial_xmit and serial_watch_cb, Paolo Bonzini, 2016/06/23
- [Qemu-devel] [PATCH v2 6/6] serial: reinstate watch after migration,
Paolo Bonzini <=
- Re: [Qemu-devel] [PATCH v2 0/6] serial: flow control fixes, Dr. David Alan Gilbert, 2016/06/24