serial/8250_pci: setup-quirk workaround for the kt serial controller
Workaround dropped notifications in the iir register. Prevent reads
coincident with new interrupt notifications by reading the iir at most
once per interrupt.
Reported-by: Nhan H Mai <nhan.h.mai@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/tty/serial/8250_pci.c b/drivers/tty/serial/8250_pci.c
index 825937a..8742ef5 100644
--- a/drivers/tty/serial/8250_pci.c
+++ b/drivers/tty/serial/8250_pci.c
@@ -1092,6 +1092,14 @@
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)
@@ -1110,7 +1118,6 @@
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
@@ -1136,6 +1143,7 @@
#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
@@ -1220,6 +1228,13 @@
.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
*/