|
 |
619821 |
From 0c6d2ffcebff88c6cda738aa46fa77c09b93b78b Mon Sep 17 00:00:00 2001
|
|
|
b28c64 |
From: Fam Zheng <famz@redhat.com>
|
|
|
619821 |
Date: Thu, 18 May 2017 09:21:27 +0200
|
|
|
b28c64 |
Subject: [PATCH 14/18] serial: only resample THR interrupt on rising edge of
|
|
|
b28c64 |
IER.THRI
|
|
|
b28c64 |
|
|
|
b28c64 |
RH-Author: Fam Zheng <famz@redhat.com>
|
|
|
619821 |
Message-id: <20170518092131.16571-15-famz@redhat.com>
|
|
|
619821 |
Patchwork-id: 75304
|
|
|
619821 |
O-Subject: [RHEL-7.4 qemu-kvm PATCH v3 14/18] serial: only resample THR interrupt on rising edge of IER.THRI
|
|
|
619821 |
Bugzilla: 1451470
|
|
|
b28c64 |
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
|
|
|
619821 |
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
|
|
|
b28c64 |
RH-Acked-by: Eduardo Habkost <ehabkost@redhat.com>
|
|
|
b28c64 |
|
|
|
b28c64 |
From: Paolo Bonzini <pbonzini@redhat.com>
|
|
|
b28c64 |
|
|
|
b28c64 |
There is disagreement on whether LSR.THRE should be resampled when
|
|
|
b28c64 |
IER.THRI goes from 1 to 1. Bochs only does it if IER.THRI goes from 0
|
|
|
b28c64 |
to 1; PCE does it even if IER.THRI is unchanged. But the Windows driver
|
|
|
b28c64 |
seems to always go from 1 to 0 and back to 1, so do things in agreement
|
|
|
b28c64 |
with Bochs, because the handling of thr_ipending was reported in 2010
|
|
|
b28c64 |
(https://lists.gnu.org/archive/html/qemu-devel/2010-03/msg01914.html)
|
|
|
b28c64 |
as breaking DR-DOS Plus.
|
|
|
b28c64 |
|
|
|
b28c64 |
Reported-by: Roy Tam <roytam@gmail.com>
|
|
|
b28c64 |
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
|
|
b28c64 |
(cherry picked from commit 1645b8eee558ffe2389a081bf61d08a864c36d2c)
|
|
|
b28c64 |
Signed-off-by: Fam Zheng <famz@redhat.com>
|
|
|
b28c64 |
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
|
|
|
b28c64 |
---
|
|
|
b28c64 |
hw/char/serial.c | 25 ++++++++++++++++---------
|
|
|
b28c64 |
1 file changed, 16 insertions(+), 9 deletions(-)
|
|
|
b28c64 |
|
|
|
b28c64 |
diff --git a/hw/char/serial.c b/hw/char/serial.c
|
|
|
b28c64 |
index e0d29a8..9986adf 100644
|
|
|
b28c64 |
--- a/hw/char/serial.c
|
|
|
b28c64 |
+++ b/hw/char/serial.c
|
|
|
b28c64 |
@@ -306,10 +306,12 @@ static void serial_ioport_write(void *opaque, hwaddr addr, uint64_t val,
|
|
|
b28c64 |
s->divider = (s->divider & 0x00ff) | (val << 8);
|
|
|
b28c64 |
serial_update_parameters(s);
|
|
|
b28c64 |
} else {
|
|
|
b28c64 |
+ uint8_t changed = (s->ier ^ val) & 0x0f;
|
|
|
b28c64 |
s->ier = val & 0x0f;
|
|
|
b28c64 |
/* If the backend device is a real serial port, turn polling of the modem
|
|
|
b28c64 |
- status lines on physical port on or off depending on UART_IER_MSI state */
|
|
|
b28c64 |
- if (s->poll_msl >= 0) {
|
|
|
b28c64 |
+ * status lines on physical port on or off depending on UART_IER_MSI state.
|
|
|
b28c64 |
+ */
|
|
|
b28c64 |
+ if ((changed & UART_IER_MSI) && s->poll_msl >= 0) {
|
|
|
b28c64 |
if (s->ier & UART_IER_MSI) {
|
|
|
b28c64 |
s->poll_msl = 1;
|
|
|
b28c64 |
serial_update_msl(s);
|
|
|
b28c64 |
@@ -324,18 +326,23 @@ static void serial_ioport_write(void *opaque, hwaddr addr, uint64_t val,
|
|
|
b28c64 |
* This is not in the datasheet, but Windows relies on it. It is
|
|
|
b28c64 |
* unclear if THRE has to be resampled every time THRI becomes
|
|
|
b28c64 |
* 1, or only on the rising edge. Bochs does the latter, and Windows
|
|
|
b28c64 |
- * always toggles IER to all zeroes and back to all ones. But for
|
|
|
b28c64 |
- * now leave it as it has always been in QEMU.
|
|
|
b28c64 |
+ * always toggles IER to all zeroes and back to all ones, so do the
|
|
|
b28c64 |
+ * same.
|
|
|
b28c64 |
*
|
|
|
b28c64 |
* If IER.THRI is zero, thr_ipending is not used. Set it to zero
|
|
|
b28c64 |
* so that the thr_ipending subsection is not migrated.
|
|
|
b28c64 |
*/
|
|
|
b28c64 |
- if ((s->ier & UART_IER_THRI) && (s->lsr & UART_LSR_THRE)) {
|
|
|
b28c64 |
- s->thr_ipending = 1;
|
|
|
b28c64 |
- } else {
|
|
|
b28c64 |
- s->thr_ipending = 0;
|
|
|
b28c64 |
+ if (changed & UART_IER_THRI) {
|
|
|
b28c64 |
+ if ((s->ier & UART_IER_THRI) && (s->lsr & UART_LSR_THRE)) {
|
|
|
b28c64 |
+ s->thr_ipending = 1;
|
|
|
b28c64 |
+ } else {
|
|
|
b28c64 |
+ s->thr_ipending = 0;
|
|
|
b28c64 |
+ }
|
|
|
b28c64 |
+ }
|
|
|
b28c64 |
+
|
|
|
b28c64 |
+ if (changed) {
|
|
|
b28c64 |
+ serial_update_irq(s);
|
|
|
b28c64 |
}
|
|
|
b28c64 |
- serial_update_irq(s);
|
|
|
b28c64 |
}
|
|
|
b28c64 |
break;
|
|
|
b28c64 |
case 2:
|
|
|
b28c64 |
--
|
|
|
b28c64 |
1.8.3.1
|
|
|
b28c64 |
|