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

commit 49b532f96fda23663f8be35593d1c1372c0f91e0 upstream.

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).

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>

diff --git a/drivers/tty/serial/8250/8250.c b/drivers/tty/serial/8250/8250.c
index 9b7336fcfbb383ea9648cd5ade7f93652ad4b788..ec7d99bf6bcfeaccb5dba0b3a8dfab77190f2110 100644 (file)
--- 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 1d4ccf8c8874573b20a15edc167f52813665da25..105dcfbd3d33282325ad14a97c5a7d23dc67cfe8 100644 (file)
--- 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 c91ace70c21d5c282f4b8b860f6fabefc2368d47..c56d114254b9e20e97bc41e064286a2320d272aa 100644 (file)
--- 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))