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| author |   Ian Jackson <ian.jackson@eu.citrix.com> | 2009-11-18 11:08:11 +0100 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@suse.de> | 2009-12-11 15:18:05 -0800 |
| commit | 68cb4f8e246bbbc649980be0628cae9265870a91 (patch) | |
| tree | ac21578ae76e640af2584726a80c20673f25ef1a /drivers | |
| parent | tty: docs: serial/tty, add to ldisc methods (diff) | |
| download | linux-dev-68cb4f8e246bbbc649980be0628cae9265870a91.tar.xz linux-dev-68cb4f8e246bbbc649980be0628cae9265870a91.zip | |
Serial: Do not read IIR in serial8250_start_tx when UART_BUG_TXEN
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>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
| -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 b75e63e9d1ee..c3e37c8e7e26 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -1339,14 +1339,12 @@ 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); } } |