The patch titled
8250: fix serial transmitter fully empty test
has been added to the -mm tree. Its filename is
8250-serial-transmitter-fully-empty-test.patch
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------------------------------------------------------
Subject: 8250: fix serial transmitter fully empty test
From: Dick Hollenbeck <dick@xxxxxxxxxxx>
When controlling an industrial radio modem it can be necessary to
manipulate the handshake lines in order to control the radio modem's
transmitter, from userspace.
The transmitter should not be turned off before all characters have been
transmitted. serial8250_tx_empty() was reporting that all characters were
transmitted before they actually were.
Signed-off-by: Dick Hollenbeck <dick@xxxxxxxxxxx>
Cc: Russell King <rmk@xxxxxxxxxxxxxxxx>
Cc: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
diff -puN drivers/serial/8250.c~8250-serial-transmitter-fully-empty-test drivers/serial/8250.c
--- a/drivers/serial/8250.c~8250-serial-transmitter-fully-empty-test
+++ a/drivers/serial/8250.c
@@ -83,6 +83,9 @@ static unsigned int skip_txen_test; /* f
#define PASS_LIMIT 256
+#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
+
+
/*
* We default to IRQ0 for the "no irq" hack. Some
* machine types want others as well - they're free
@@ -1794,7 +1797,7 @@ static unsigned int serial8250_tx_empty(
up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
spin_unlock_irqrestore(&up->port.lock, flags);
- return lsr & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
+ return (lsr & BOTH_EMPTY) == BOTH_EMPTY ? TIOCSER_TEMT : 0;
}
static unsigned int serial8250_get_mctrl(struct uart_port *port)
@@ -1852,8 +1855,6 @@ static void serial8250_break_ctl(struct
spin_unlock_irqrestore(&up->port.lock, flags);
}
-#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
-
/*
* Wait for transmitter & holding register to empty
*/
_
Patches currently in -mm which might be from dick@xxxxxxxxxxx are
8250-serial-transmitter-fully-empty-test.patch
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