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 <[email protected]> --- 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 -- You received this message because you are subscribed to the Google Groups "Jailhouse" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/jailhouse-dev/20190812112152.693622-1-ralf.ramsauer%40oth-regensburg.de.
