HPET_TN_FSB is not a proper mask bit; it merely toggles between MSI and
legacy interrupt delivery. The proper mask bit is HPET_TN_ENABLE, so
use both bits when (un)masking the interrupt.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/5093E09002000078000A60E6@nat28.tlf.novell.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
 
 
        /* unmask it */
        cfg = hpet_readl(HPET_Tn_CFG(hdev->num));
-       cfg |= HPET_TN_FSB;
+       cfg |= HPET_TN_ENABLE | HPET_TN_FSB;
        hpet_writel(cfg, HPET_Tn_CFG(hdev->num));
 }
 
 
        /* mask it */
        cfg = hpet_readl(HPET_Tn_CFG(hdev->num));
-       cfg &= ~HPET_TN_FSB;
+       cfg &= ~(HPET_TN_ENABLE | HPET_TN_FSB);
        hpet_writel(cfg, HPET_Tn_CFG(hdev->num));
 }