From: Valmer Huhn <valmer.huhn@xxxxxxxxxxxxxxxxx> commit c6b9e95dde7b54e6a53c47241201ab5a4035c320 upstream. The following in 8250_exar.c line 589 is used to determine the number of ports for each Exar board: nr_ports = board->num_ports ? board->num_ports : pcidev->device & 0x0f; If the number of ports a card has is not explicitly specified, it defaults to the rightmost 4 bits of the PCI device ID. This is prone to error since not all PCI device IDs contain a number which corresponds to the number of ports that card provides. This particular case involves COMMTECH_4222PCIE, COMMTECH_4224PCIE and COMMTECH_4228PCIE cards with device IDs 0x0022, 0x0020 and 0x0021. Currently the multiport cards receive 2, 0 and 1 port instead of 2, 4 and 8 ports respectively. To fix this, each Commtech Fastcom PCIe card is given a struct where the number of ports is explicitly specified. This ensures 'board->num_ports' is used instead of the default 'pcidev->device & 0x0f'. Fixes: d0aeaa83f0b0 ("serial: exar: split out the exar code from 8250_pci") Signed-off-by: Valmer Huhn <valmer.huhn@xxxxxxxxxxxxxxxxx> Tested-by: Valmer Huhn <valmer.huhn@xxxxxxxxxxxxxxxxx> Cc: stable <stable@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20200813165255.GC345440@xxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/tty/serial/8250/8250_exar.c | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-) --- a/drivers/tty/serial/8250/8250_exar.c +++ b/drivers/tty/serial/8250/8250_exar.c @@ -744,6 +744,24 @@ static const struct exar8250_board pbn_e .exit = pci_xr17v35x_exit, }; +static const struct exar8250_board pbn_fastcom35x_2 = { + .num_ports = 2, + .setup = pci_xr17v35x_setup, + .exit = pci_xr17v35x_exit, +}; + +static const struct exar8250_board pbn_fastcom35x_4 = { + .num_ports = 4, + .setup = pci_xr17v35x_setup, + .exit = pci_xr17v35x_exit, +}; + +static const struct exar8250_board pbn_fastcom35x_8 = { + .num_ports = 8, + .setup = pci_xr17v35x_setup, + .exit = pci_xr17v35x_exit, +}; + static const struct exar8250_board pbn_exar_XR17V4358 = { .num_ports = 12, .setup = pci_xr17v35x_setup, @@ -811,9 +829,9 @@ static const struct pci_device_id exar_p EXAR_DEVICE(EXAR, XR17V358, pbn_exar_XR17V35x), EXAR_DEVICE(EXAR, XR17V4358, pbn_exar_XR17V4358), EXAR_DEVICE(EXAR, XR17V8358, pbn_exar_XR17V8358), - EXAR_DEVICE(COMMTECH, 4222PCIE, pbn_exar_XR17V35x), - EXAR_DEVICE(COMMTECH, 4224PCIE, pbn_exar_XR17V35x), - EXAR_DEVICE(COMMTECH, 4228PCIE, pbn_exar_XR17V35x), + EXAR_DEVICE(COMMTECH, 4222PCIE, pbn_fastcom35x_2), + EXAR_DEVICE(COMMTECH, 4224PCIE, pbn_fastcom35x_4), + EXAR_DEVICE(COMMTECH, 4228PCIE, pbn_fastcom35x_8), EXAR_DEVICE(COMMTECH, 4222PCI335, pbn_fastcom335_2), EXAR_DEVICE(COMMTECH, 4224PCI335, pbn_fastcom335_4),