From 49b532f96fda23663f8be35593d1c1372c0f91e0 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Fri, 6 Apr 2012 11:49:44 -0700 Subject: 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 Acked-by: Alan Cox Cc: Sudhakar Mamillapalli Reported-by: Nhan H Mai Signed-off-by: Dan Williams Signed-off-by: Greg Kroah-Hartman --- include/linux/serial_core.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include') 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)) -- cgit v1.2.3 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 --- drivers/tty/serial/8250/8250.c | 8 +++++--- drivers/tty/serial/8250/8250_pci.c | 17 ++++++++++++++++- include/linux/serial_core.h | 1 + 3 files changed, 22 insertions(+), 4 deletions(-) (limited to 'include') diff --git a/drivers/tty/serial/8250/8250.c b/drivers/tty/serial/8250/8250.c index 56492d208a7a..5c27f7e6c9f1 100644 --- a/drivers/tty/serial/8250/8250.c +++ b/drivers/tty/serial/8250/8250.c @@ -2035,10 +2035,12 @@ static int serial8250_startup(struct uart_port *port) spin_unlock_irqrestore(&port->lock, flags); /* - * If the interrupt is not reasserted, setup a timer to - * kick the UART on a regular basis. + * If the interrupt is not reasserted, or we otherwise + * don't trust the iir, setup a timer to kick the UART + * on a regular basis. */ - if (!(iir1 & UART_IIR_NO_INT) && (iir & UART_IIR_NO_INT)) { + if ((!(iir1 & UART_IIR_NO_INT) && (iir & UART_IIR_NO_INT)) || + up->port.flags & UPF_BUG_THRE) { up->bugs |= UART_BUG_THRE; pr_debug("ttyS%d - using backup timer\n", serial_index(port)); diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c index 105dcfbd3d33..858dca865d6a 100644 --- a/drivers/tty/serial/8250/8250_pci.c +++ b/drivers/tty/serial/8250/8250_pci.c @@ -1092,6 +1092,14 @@ static int skip_tx_en_setup(struct serial_private *priv, return pci_default_setup(priv, board, port, idx); } +static int kt_serial_setup(struct serial_private *priv, + const struct pciserial_board *board, + struct uart_port *port, int idx) +{ + port->flags |= UPF_BUG_THRE; + return skip_tx_en_setup(priv, board, port, idx); +} + static int pci_eg20t_init(struct pci_dev *dev) { #if defined(CONFIG_SERIAL_PCH_UART) || defined(CONFIG_SERIAL_PCH_UART_MODULE) @@ -1110,7 +1118,6 @@ pci_xr17c154_setup(struct serial_private *priv, return pci_default_setup(priv, board, port, idx); } -/* This should be in linux/pci_ids.h */ #define PCI_VENDOR_ID_SBSMODULARIO 0x124B #define PCI_SUBVENDOR_ID_SBSMODULARIO 0x124B #define PCI_DEVICE_ID_OCTPRO 0x0001 @@ -1140,6 +1147,7 @@ pci_xr17c154_setup(struct serial_private *priv, #define PCI_DEVICE_ID_OXSEMI_16PCI958 0x9538 #define PCIE_DEVICE_ID_NEO_2_OX_IBM 0x00F6 #define PCI_DEVICE_ID_PLX_CRONYX_OMEGA 0xc001 +#define PCI_DEVICE_ID_INTEL_PATSBURG_KT 0x1d3d /* Unknown vendors/cards - this should not be in linux/pci_ids.h */ #define PCI_SUBDEVICE_ID_UNKNOWN_0x1584 0x1584 @@ -1224,6 +1232,13 @@ static struct pci_serial_quirk pci_serial_quirks[] __refdata = { .subdevice = PCI_ANY_ID, .setup = ce4100_serial_setup, }, + { + .vendor = PCI_VENDOR_ID_INTEL, + .device = PCI_DEVICE_ID_INTEL_PATSBURG_KT, + .subvendor = PCI_ANY_ID, + .subdevice = PCI_ANY_ID, + .setup = kt_serial_setup, + }, /* * ITE */ 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 v1.2.3