Revert "serial/8250_pci: setup-quirk workaround for the kt serial controller"

This reverts commit 448ac154c957c4580531fa0c8f2045816fe2f0e7.

The semantic of UPF_IIR_ONCE is only guaranteed to workaround the race
condition in the kt serial's iir register if the only source of
interrupts is THRE (fifo-empty) events.  An modem status event at the
wrong time can again cause an iir read to drop the 'empty' status
leading to a hang.  So, revert this in preparation for using the
existing "I don't trust my iir register" workaround in the 8250 core
(UART_BUG_THRE).

[stable: 3.3.x]
Cc: stable <stable@vger.kernel.org>
Acked-by: Alan Cox <alan@linux.intel.com>
Cc: Sudhakar Mamillapalli <sudhakar@fb.com>
Reported-by: Nhan H Mai <nhan.h.mai@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 0 insertions, 1 deletions

diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index f51bf2e70c69..882f1d61aa56 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -357,7 +357,6 @@ struct uart_port {
 #define UPF_CONS_FLOW           ((__force upf_t) (1 << 23))
 #define UPF_SHARE_IRQ           ((__force upf_t) (1 << 24))
 #define UPF_EXAR_EFR            ((__force upf_t) (1 << 25))
-#define UPF_IIR_ONCE            ((__force upf_t) (1 << 26))
 /* The exact UART type is known and should not be probed.  */
 #define UPF_FIXED_TYPE          ((__force upf_t) (1 << 27))
 #define UPF_BOOT_AUTOCONF       ((__force upf_t) (1 << 28))