diff options
| author | Ian Jackson <ian.jackson@eu.citrix.com> | 2009-11-18 11:08:11 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-12-18 13:43:48 -0800 |
| commit | 77e856d7f3de1bfb26f96314ed6e868fe4f38877 (patch) | |
| tree | 80f79b5e08954fb392defe70d86c1fba91ef3a0d | |
| parent | 7c52c4436288e1eec78edaca6366658b33fb54e2 (diff) | |
Serial: Do not read IIR in serial8250_start_tx when UART_BUG_TXEN
commit 68cb4f8e246bbbc649980be0628cae9265870a91 upstream.
Do not read IIR in serial8250_start_tx when UART_BUG_TXEN
Reading the IIR clears some oustanding interrupts so it is not safe.
Instead, simply transmit immediately if the buffer is empty without
regard to IIR.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Jiri Kosina <jkosina@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | drivers/serial/8250.c | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index fb867a9f55e..524f6ab5e05 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -1337,14 +1337,12 @@ static void serial8250_start_tx(struct uart_port *port) serial_out(up, UART_IER, up->ier); if (up->bugs & UART_BUG_TXEN) { - unsigned char lsr, iir; + unsigned char lsr; lsr = serial_in(up, UART_LSR); up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS; - iir = serial_in(up, UART_IIR) & 0x0f; if ((up->port.type == PORT_RM9000) ? - (lsr & UART_LSR_THRE && - (iir == UART_IIR_NO_INT || iir == UART_IIR_THRI)) : - (lsr & UART_LSR_TEMT && iir & UART_IIR_NO_INT)) + (lsr & UART_LSR_THRE) : + (lsr & UART_LSR_TEMT)) transmit_chars(up); } } |