Re: [Xen-devel] [PATCHv1] x86: rtc_cmos platform device requires legacy irqs

From: Boris Ostrovsky
Date: Tue Dec 08 2015 - 16:16:14 EST


On 12/08/2015 04:02 PM, Thomas Gleixner wrote:
On Fri, 4 Dec 2015, David Vrabel wrote:
On 04/12/15 14:06, David Vrabel wrote:
On 03/12/15 10:43, David Vrabel wrote:
Adding the rtc platform device when there are no legacy irqs (no
legacy PIC) causes a conflict with other devices that end up using the
same irq number.
An alternative is to remove the rtc_cmos platform device in Xen PV
guests.

Any preference on how this regression should be fixed?

David

8<--------------------------
x86: Xen PV guests don't have the rtc_cmos platform device

[...]
--- a/arch/x86/kernel/rtc.c
+++ b/arch/x86/kernel/rtc.c
@@ -200,6 +200,9 @@ static __init int add_rtc_cmos(void)
}
#endif
+ if (xen_pv_domain())
+ return -ENODEV;
+
Note there's a missing include that breaks !XEN builds.
What's the state of this?

I think we are waiting for x86 maintainers to express their preference. There were 3 proposals to add in add_rtc_cmos()

1. if (!nr_legacy_irqs())
return -ENODEV;

2. #ifdef XEN
if (xen_pv_domain())
return -ENODEV;
#endif

3. if (paravirt_enabled())
return -ENODEV;


-boris
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