[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen staging-4.16] ns16550: use poll mode if INTERRUPT_LINE is 0xff
commit f1be0b62a03b90a40a03e21f965e4cbb89809bb1 Author: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx> AuthorDate: Tue Jun 7 14:07:34 2022 +0200 Commit: Jan Beulich <jbeulich@xxxxxxxx> CommitDate: Tue Jun 7 14:07:34 2022 +0200 ns16550: use poll mode if INTERRUPT_LINE is 0xff Intel LPSS has INTERRUPT_LINE set to 0xff by default, that is declared by the PCI Local Bus Specification Revision 3.0 (from 2004) as "unknown"/"no connection". Fallback to poll mode in this case. The 0xff handling is x86-specific, the surrounding code is guarded with CONFIG_X86 anyway. Signed-off-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx> Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx> master commit: 6a2ea1a2370a0c8a0210accac0ae62e68c185134 master date: 2022-05-20 12:19:45 +0200 --- xen/drivers/char/ns16550.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/xen/drivers/char/ns16550.c b/xen/drivers/char/ns16550.c index 30596d60d4..2d2bd2a024 100644 --- a/xen/drivers/char/ns16550.c +++ b/xen/drivers/char/ns16550.c @@ -1221,6 +1221,19 @@ pci_uart_config(struct ns16550 *uart, bool_t skip_amt, unsigned int idx) pci_conf_read8(PCI_SBDF(0, b, d, f), PCI_INTERRUPT_LINE) : 0; +#ifdef CONFIG_X86 + /* + * PCI Local Bus Specification Revision 3.0 defines 0xff value + * as special only for X86. + */ + if ( uart->irq == 0xff ) + uart->irq = 0; +#endif + if ( !uart->irq ) + printk(XENLOG_INFO + "ns16550: %pp: no legacy IRQ, using poll mode\n", + &PCI_SBDF(0, b, d, f)); + return 0; } } -- generated by git-patchbot for /home/xen/git/xen.git#staging-4.16
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