The patch titled
serial/8250.c: IRQ handling race and spurious IIR read
has been removed from the -mm tree. Its filename was
serial-8250c-irq-handling-race-and-spurious-iir-read.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: serial/8250.c: IRQ handling race and spurious IIR read
From: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxx>
Reviewed-by: Markus Armbruster <armbru@xxxxxxxxxx>
Cc: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/serial/8250.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff -puN drivers/serial/8250.c~serial-8250c-irq-handling-race-and-spurious-iir-read drivers/serial/8250.c
--- a/drivers/serial/8250.c~serial-8250c-irq-handling-race-and-spurious-iir-read
+++ a/drivers/serial/8250.c
@@ -1337,14 +1337,12 @@ static void serial8250_start_tx(struct u
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);
}
}
_
Patches currently in -mm which might be from ian.jackson@xxxxxxxxxxxxx are
linux-next.patch
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