On Wed, May 11, 2022 at 03:59:28PM +0200, 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 <[email protected]> > --- > Changes in v4: > - adjust log message, change it from WARNING to INFO > - re-add x86 reference in the commit message > Changes in v3: > - change back to checking 0xff explicitly > - adjust commit message, include spec reference > - change warning to match the above > Changes in v2: > - add log message > - extend commit message > - code style fix > --- > xen/drivers/char/ns16550.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/xen/drivers/char/ns16550.c b/xen/drivers/char/ns16550.c > index fb75cee4a13a..c0d65cff62fe 100644 > --- a/xen/drivers/char/ns16550.c > +++ b/xen/drivers/char/ns16550.c > @@ -1238,6 +1238,13 @@ 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; > > + if ( uart->irq == 0xff ) > + uart->irq = 0; > + if ( !uart->irq ) > + printk(XENLOG_INFO > + "ns16550: %pp no legacy IRQ %d, using poll > mode\n", > + &PCI_SBDF(0, b, d, f), uart->irq);
There's no point in printing ->irq as it will be 0 or else the message won't be printed. With that fixed: Reviewed-by: Roger Pau Monné <[email protected]> Thanks.
