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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