On 20.05.2022 10:53, Marek Marczykowski-Górecki wrote: > 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 <marma...@invisiblethingslab.com> > Reviewed-by: Roger Pau Monné <roger....@citrix.com>
Reviewed-by: Jan Beulich <jbeul...@suse.com> > Changes in v6: > - wrap the check in additional CONFIG_X86, with appropriate comment Thanks, albeit ... > --- a/xen/drivers/char/ns16550.c > +++ b/xen/drivers/char/ns16550.c > @@ -1238,6 +1238,17 @@ 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 */ ... I'll have to remember to correct the style of the comment while committing ... > + if ( uart->irq == 0xff ) > + uart->irq = 0; > +#endif > + if ( !uart->irq ) > + printk(XENLOG_INFO > + "ns16550: %pp no legacy IRQ, using poll mode\n", ... and perhaps insert another colon after %pp here. Jan > + &PCI_SBDF(0, b, d, f)); > + > return 0; > } > }
