Messages in this thread Patch in this message | | | Date | Fri, 4 Dec 2015 14:06:06 +0000 | From | David Vrabel <> | Subject | Re: [Xen-devel] [PATCHv1] x86: rtc_cmos platform device requires legacy irqs |
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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
Adding the rtc platform device in a Xen PV guests causes an IRQ conflict because these guests do not have a legacy PIC.
In a single VCPU Xen PV guest we should have:
/proc/interrupts: CPU0 0: 4934 xen-percpu-virq timer0 1: 0 xen-percpu-ipi spinlock0 2: 0 xen-percpu-ipi resched0 3: 0 xen-percpu-ipi callfunc0 4: 0 xen-percpu-virq debug0 5: 0 xen-percpu-ipi callfuncsingle0 6: 0 xen-percpu-ipi irqwork0 7: 321 xen-dyn-event xenbus 8: 90 xen-dyn-event hvc_console ...
But hvc_console cannot get its interrupt because it is already in use by rtc0 and the console does not work.
genirq: Flags mismatch irq 8. 00000000 (hvc_console) vs. 00000000 (rtc0)
So don't add the rtc_cmos device in Xen PV guests.
Reported-by: Sander Eikelenboom <linux@eikelenboom.it> Signed-off-by: David Vrabel <david.vrabel@citrix.com> Tested-by: Sander Eikelenboom <linux@eikelenboom.it> --- arch/x86/kernel/rtc.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c index cd96852..7b190b8 100644 --- 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; + platform_device_register(&rtc_device); dev_info(&rtc_device.dev, "registered platform RTC device (no PNP device found)\n"); -- 2.1.4
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