[Xen-devel] [PATCH] make c/s 21089 work again with c/s 21092

["Jan Beulich" <JBeulich@xxxxxxxxxx>]

Unfortunately the latter c/s' change to mpparse.c yielded the former
patch non-functional - Xen's serial port IRQ is not in IQR_DISABLED
state, yet must be allowed to get its trigger mode and polarity set
up in order for it to be usable.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

--- 2010-04-13.orig/xen/arch/x86/mpparse.c      2010-04-13 15:25:22.000000000 
+0200
+++ 2010-04-13/xen/arch/x86/mpparse.c   2010-04-13 15:26:38.000000000 +0200
@@ -1103,6 +1103,8 @@ int mp_register_gsi (u32 gsi, int trigge
        int                     ioapic = -1;
        int                     ioapic_pin = 0;
        int                     idx, bit = 0;
+       struct irq_desc *       desc;
+       unsigned long           flags;
 
        /*
         * Mapping between Global System Interrups, which
@@ -1127,8 +1129,13 @@ int mp_register_gsi (u32 gsi, int trigge
        if (ioapic_renumber_irq)
                gsi = ioapic_renumber_irq(ioapic, gsi);
 
-       if (!(irq_to_desc(gsi)->status & IRQ_DISABLED))
+       desc = irq_to_desc(gsi);
+       spin_lock_irqsave(&desc->lock, flags);
+       if (!(desc->status & IRQ_DISABLED) && desc->handler != &no_irq_type) {
+               spin_unlock_irqrestore(&desc->lock, flags);
                return -EEXIST;
+       }
+       spin_unlock_irqrestore(&desc->lock, flags);
 
        /* 
         * Avoid pin reprogramming.  PRTs typically include entries

x86-startup-irq-from-setup-gsi-fix2.patch
Description: Text document

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