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

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This reverts commit 448ac154c9.

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>
This commit is contained in:
Dan Williams 2012-04-06 11:49:44 -07:00 committed by Greg Kroah-Hartman
parent 3579812373
commit 49b532f96f
3 changed files with 2 additions and 20 deletions
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4
drivers/tty/serial/8250/8250.c
View file

@ -1572,13 +1572,11 @@ static irqreturn_t serial8250_interrupt(int irq, void *dev_id)
do {
struct uart_8250_port *up;
struct uart_port *port;
bool skip;
up = list_entry(l, struct uart_8250_port, list);
port = &up->port;
skip = pass_counter && up->port.flags & UPF_IIR_ONCE;
if (!skip && port->handle_irq(port)) {
if (port->handle_irq(port)) {
handled = 1;
end = NULL;
} else if (end == NULL)

17
drivers/tty/serial/8250/8250_pci.c
View file

@ -1092,14 +1092,6 @@ 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_IIR_ONCE;
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)
@ -1118,6 +1110,7 @@ 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
@ -1147,7 +1140,6 @@ 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
@ -1232,13 +1224,6 @@ 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
*/

1
include/linux/serial_core.h
View file

@ -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))