There may be setups, where legacy interrupts are not available. This is
the caese, e.g., when Linux runs as guest (aka. non-root cell) of the
partitioning hypervisor Jailhouse. There, only MSI(-X) interrupts are
available for guests.
But the 8250_pci driver currently only supports legacy ints. So let's
enable MSI(-X) interrupts.
Nevertheless, this needs to handled with care: while many 8250 devices
actually claim to support MSI(-X) interrupts it should not be enabled be
default. I had at least one device in my hands with broken MSI
implementation.
So better introduce a whitelist with devices that are known to support
MSI(-X) interrupts. I tested all devices mentioned in the patch.
Signed-off-by: Ralf Ramsauer <ralf.ramsauer@xxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/8250/8250_pci.c | 27 ++++++++++++++++++++++++++-
1 file changed, 26 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index bbe5cba21522..97992884c0ee 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -53,6 +53,16 @@ struct serial_private {
int line[0];
};
+static const struct pci_device_id pci_use_msi[] = {
+ { PCI_DEVICE_SUB(PCI_VENDOR_ID_NETMOS, PCI_DEVICE_ID_NETMOS_9900,
+ 0xA000, 0x1000) },
+ { PCI_DEVICE_SUB(PCI_VENDOR_ID_NETMOS, PCI_DEVICE_ID_NETMOS_9912,
+ 0xA000, 0x1000) },
+ { PCI_DEVICE_SUB(PCI_VENDOR_ID_NETMOS, PCI_DEVICE_ID_NETMOS_9922,
+ 0xA000, 0x1000) },
+ { }
+};
+
static int pci_default_setup(struct serial_private*,
const struct pciserial_board*, struct uart_8250_port *, int);
@@ -3643,7 +3653,22 @@ pciserial_init_ports(struct pci_dev *dev, const struct pciserial_board *board)
memset(&uart, 0, sizeof(uart));
uart.port.flags = UPF_SKIP_TEST | UPF_BOOT_AUTOCONF | UPF_SHARE_IRQ;
uart.port.uartclk = board->base_baud * 16;
- uart.port.irq = get_pci_irq(dev, board);
+
+ if (pci_match_id(pci_use_msi, dev)) {
+ dev_dbg(&dev->dev, "Using MSI(-X) interrupts\n");
+ pci_set_master(dev);
+ rc = pci_alloc_irq_vectors(dev, 1, 1, PCI_IRQ_ALL_TYPES);
+ } else {
+ dev_dbg(&dev->dev, "Using legacy interrupts\n");
+ rc = pci_alloc_irq_vectors(dev, 1, 1, PCI_IRQ_LEGACY);
+ }
+ if (rc < 0) {
+ kfree(priv);
+ priv = ERR_PTR(rc);
+ goto err_deinit;
+ }
+
+ uart.port.irq = pci_irq_vector(dev, 0);
uart.port.dev = &dev->dev;
for (i = 0; i < nr_ports; i++) {
--
2.22.0
