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path: root/drivers/serial/pmac_zilog.c
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Diffstat (limited to 'drivers/serial/pmac_zilog.c')
-rw-r--r--drivers/serial/pmac_zilog.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/serial/pmac_zilog.c b/drivers/serial/pmac_zilog.c
index 0700cd10b97c..683e66f18e8c 100644
--- a/drivers/serial/pmac_zilog.c
+++ b/drivers/serial/pmac_zilog.c
@@ -411,6 +411,17 @@ static void pmz_transmit_chars(struct uart_pmac_port *uap)
goto ack_tx_int;
}
+ /* Under some circumstances, we see interrupts reported for
+ * a closed channel. The interrupt mask in R1 is clear, but
+ * R3 still signals the interrupts and we see them when taking
+ * an interrupt for the other channel (this could be a qemu
+ * bug but since the ESCC doc doesn't specify precsiely whether
+ * R3 interrup status bits are masked by R1 interrupt enable
+ * bits, better safe than sorry). --BenH.
+ */
+ if (!ZS_IS_OPEN(uap))
+ goto ack_tx_int;
+
if (uap->port.x_char) {
uap->flags |= PMACZILOG_FLAG_TX_ACTIVE;
write_zsdata(uap, uap->port.x_char);
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