Please note that the same issue appears to have been introduced in the recent 4.2.7 kernel. It perhaps has to do with b4ff8389ed14b849354b59ce9b360bdefcdbf99c having a matching commit e8d097151d309eb71f750bbf34e6a7ef6256da7e in linux-stable.git. The below patch to arch/x86/kernel/rtc.c was also effective for 4.2.7.
Eric On 2015-12-02 18:30, Sander Eikelenboom wrote: > On 2015-12-02 15:55, David Vrabel wrote: > > On 28/11/15 15:47, Sander Eikelenboom wrote: > >> genirq: Flags mismatch irq 8. 00000000 (hvc_console) vs. 00000000 > >> (rtc0) > > > > We shouldn't register an rtc_cmos device because its legacy irq > > conflicts with the irq needed for hvc0. For a multi VCPU guest irq 8 > > is > > in use for the pv spinlocks and this gets requested first, preventing > > the rtc device from probing. > > > > Does this patch fix it for you? > > > > David > > It does, thanks. > > Reported-and-tested-by: Sander Eikelenboom <li...@eikelenboom.it> > > -- > Sander > > > 8<-------------------- > > x86: rtc_cmos platform device requires legacy irqs > > > > 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. > > > > In a single VCPU 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) > > > > The rtc_cmos device requires a particular legacy irq so don't add it > > if there are no legacy irqs. > > > > Signed-off-by: David Vrabel <david.vra...@citrix.com> > > --- > > arch/x86/kernel/rtc.c | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c > > index cd96852..07c70f1 100644 > > --- a/arch/x86/kernel/rtc.c > > +++ b/arch/x86/kernel/rtc.c > > @@ -14,6 +14,7 @@ > > #include <asm/time.h> > > #include <asm/intel-mid.h> > > #include <asm/rtc.h> > > +#include <asm/i8259.h> > > > > #ifdef CONFIG_X86_32 > > /* > > @@ -200,6 +201,10 @@ static __init int add_rtc_cmos(void) > > } > > #endif > > > > + /* RTC uses legacy IRQs. */ > > + if (!nr_legacy_irqs()) > > + return -ENODEV; > > + > > platform_device_register(&rtc_device); > > dev_info(&rtc_device.dev, > > "registered platform RTC device (no PNP device found)\n");
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