* Paolo Bonzini (pbonz...@redhat.com) wrote:
>
>
> On 22/06/2016 17:05, Dr. David Alan Gilbert wrote:
> > * Paolo Bonzini (pbonz...@redhat.com) wrote:
> >> Otherwise, a serial port can get stuck if it is migrated while flow control
> >> is in effect.
> >>
> >> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
> >> ---
> >> hw/char/serial.c | 16 ++++++++++++++--
> >> include/hw/char/serial.h | 1 +
> >> 2 files changed, 15 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/hw/char/serial.c b/hw/char/serial.c
> >> index e65e9e0..6f0a49e 100644
> >> --- a/hw/char/serial.c
> >> +++ b/hw/char/serial.c
> >> @@ -639,8 +639,20 @@ 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;
> >
> > Why remove the check you just added?
>
> Because I'm dumb. :)
>
> >> +
> >> + if (s->tsr_retry > 0) {
> >> + /* tsr_retry > 0 implies LSR.TEMT = 0 (transmitter not empty). */
> >> + if (s->lsr & UART_LSR_TEMT) {
> >> + return -1;
> >> + }
> >> +
> >> + assert(s->watch_tag == 0);
> >> + s->watch_tag = qemu_chr_fe_add_watch(s->chr, G_IO_OUT|G_IO_HUP,
> >> serial_xmit, s);
> >> + } else {
> >> + /* tsr_retry == 0 implies LSR.TEMT = 1 (transmitter empty). */
> >> + if (!(s->lsr & UART_LSR_TEMT)) {
> >> + return -1;
> >
> > If you're failing migration (-1) then please error_report to say why
> > so when someone hits it I can immediately see why.
>
> Ok, something like
>
> error_report("inconsistent state in serial device");
>
> ?
Yeh, feel free to add tsr_retry and lsr to the message as well so that if you're
looking at it you can figure out what happened.
Dave
>
> Paolo
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
