Revert "serial/8250_pci: setup-quirk workaround for the kt serial controller"
authorDan Williams <dan.j.williams@intel.com>
Fri, 6 Apr 2012 18:49:44 +0000 (11:49 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Mon, 9 Apr 2012 17:34:52 +0000 (10:34 -0700)
commit49b532f96fda23663f8be35593d1c1372c0f91e0
tree778aacfa431d612f03a136847a0ebe84a9ffe82a
parent3579812373aba92b2f3b632bdf99329bc3c05d62
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>
drivers/tty/serial/8250/8250.c
drivers/tty/serial/8250/8250_pci.c
include/linux/serial_core.h