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@xxxxxxxxxxxxxxx>
Cc: Alan Cox <alan@xxxxxxxxxxxxxxx>
Cc: Sudhakar Mamillapalli <sudhakar@xxxxxx>
Reported-by: Nhan H Mai <nhan.h.mai@xxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
drivers/tty/serial/8250/8250.c | 4 +---
drivers/tty/serial/8250/8250_pci.c | 17 +----------------
include/linux/serial_core.h | 1 -
3 files changed, 2 insertions(+), 20 deletions(-)
diff --git a/drivers/tty/serial/8250/8250.c b/drivers/tty/serial/8250/8250.c
index 9b7336f..ec7d99b 100644
--- a/drivers/tty/serial/8250/8250.c
+++ b/drivers/tty/serial/8250/8250.c
@@ -1592,13 +1592,11 @@ 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)
diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index 1d4ccf8..105dcfb 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -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
*/
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index c91ace7..c56d114 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -355,7 +355,6 @@ 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))
--
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