2 files changed, 26 insertions, 4 deletions

diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c
index 5f197e197c55..7ce09492fc0c 100644
--- a/arch/i386/kernel/apic.c
+++ b/arch/i386/kernel/apic.c
@@ -157,7 +157,7 @@ void clear_local_APIC(void)
         maxlvt = get_maxlvt();
 
         /*
-         * Masking an LVT entry on a P6 can trigger a local APIC error
+         * Masking an LVT entry can trigger a local APIC error
          * if the vector is zero. Mask LVTERR first to prevent this.
          */
         if (maxlvt >= 3) {
@@ -1118,7 +1118,18 @@ void disable_APIC_timer(void)
                 unsigned long v;
 
                 v = apic_read(APIC_LVTT);
-                apic_write_around(APIC_LVTT, v | APIC_LVT_MASKED);
+                /*
+                 * When an illegal vector value (0-15) is written to an LVT
+                 * entry and delivery mode is Fixed, the APIC may signal an
+                 * illegal vector error, with out regard to whether the mask
+                 * bit is set or whether an interrupt is actually seen on input.
+                 *
+                 * Boot sequence might call this function when the LVTT has
+                 * '0' vector value. So make sure vector field is set to
+                 * valid value.
+                 */
+                v |= (APIC_LVT_MASKED | LOCAL_TIMER_VECTOR);
+                apic_write_around(APIC_LVTT, v);
         }
 }
 
diff --git a/arch/x86_64/kernel/apic.c b/arch/x86_64/kernel/apic.c
index 396e125cb212..b2ead91df218 100644
--- a/arch/x86_64/kernel/apic.c
+++ b/arch/x86_64/kernel/apic.c
@@ -100,7 +100,7 @@ void clear_local_APIC(void)
         maxlvt = get_maxlvt();
 
         /*
-         * Masking an LVT entry on a P6 can trigger a local APIC error
+         * Masking an LVT entry can trigger a local APIC error
          * if the vector is zero. Mask LVTERR first to prevent this.
          */
         if (maxlvt >= 3) {
@@ -851,7 +851,18 @@ void disable_APIC_timer(void)
                 unsigned long v;
 
                 v = apic_read(APIC_LVTT);
-                apic_write(APIC_LVTT, v | APIC_LVT_MASKED);
+                /*
+                 * When an illegal vector value (0-15) is written to an LVT
+                 * entry and delivery mode is Fixed, the APIC may signal an
+                 * illegal vector error, with out regard to whether the mask
+                 * bit is set or whether an interrupt is actually seen on input.
+                 *
+                 * Boot sequence might call this function when the LVTT has
+                 * '0' vector value. So make sure vector field is set to
+                 * valid value.
+                 */
+                v |= (APIC_LVT_MASKED | LOCAL_TIMER_VECTOR);
+                apic_write(APIC_LVTT, v);
         }
 }