From bc02d15a3452fdf9276e8fb89c5e504a88df888a Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Fri, 6 Apr 2012 11:49:50 -0700 Subject: 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 Cc: stable Reported-by: Nhan H Mai Reported-by: Sudhakar Mamillapalli Tested-by: Nhan H Mai Tested-by: Sudhakar Mamillapalli Signed-off-by: Dan Williams Signed-off-by: Greg Kroah-Hartman --- include/linux/serial_core.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/serial_core.h') diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 882f1d61aa56..2db407a40051 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)) -- cgit v1.2.1