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serial: 8250: Don't delay after transmitter is ready. 

The loop in wait_for_xmitr() is delaying one extra uS after the ready
condition has been met.  Rewrite the loop to only delay if the
transmitter is not ready.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
David Daney 2010-10-05 11:40:07 -07:00 committed by Greg Kroah-Hartman
parent fd8b6cb4d8
commit 97d303b765
1 changed files with 4 additions and 2 deletions
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6
drivers/serial/8250.c
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@ -1867,15 +1867,17 @@ static void wait_for_xmitr(struct uart_8250_port *up, int bits)
unsigned int status, tmout = 10000;
/* Wait up to 10ms for the character(s) to be sent. */
do {
for (;;) {
status = serial_in(up, UART_LSR);
up->lsr_saved_flags |= status & LSR_SAVE_FLAGS;
if ((status & bits) == bits)
break;
if (--tmout == 0)
break;
udelay(1);
} while ((status & bits) != bits);
}
/* Wait up to 1s for flow control if necessary */
if (up->port.flags & UPF_CONS_FLOW) {