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authorDan Williams <dan.j.williams@intel.com>2012-04-06 11:49:50 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-04-09 10:38:30 -0700
commitbc02d15a3452fdf9276e8fb89c5e504a88df888a (patch)
treeb7014c75d121418b0bc88d8c74f699f9a59adc24 /include
parent49b532f96fda23663f8be35593d1c1372c0f91e0 (diff)
serial/8250_pci: add a "force background timer" flag and use it for the "kt" serial port
Workaround dropped notifications in the iir register. Register reads coincident with new interrupt notifications sometimes result in this device clearing the interrupt event without reporting it in the read data. The serial core already has a heuristic for determining when a device has an untrustworthy iir register. In this case when we apriori know that the iir is faulty use a flag (UPF_BUG_THRE) to bypass the test and force usage of the background timer. [stable: 3.3.x] Acked-by: Alan Cox <alan@linux.intel.com> Cc: stable <stable@vger.kernel.org> Reported-by: Nhan H Mai <nhan.h.mai@intel.com> Reported-by: Sudhakar Mamillapalli <sudhakar@fb.com> Tested-by: Nhan H Mai <nhan.h.mai@intel.com> Tested-by: Sudhakar Mamillapalli <sudhakar@fb.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/serial_core.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 882f1d61aa5..2db407a4005 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -357,6 +357,7 @@ 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_BUG_THRE ((__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))