diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 89d3fd4c3cd2..2278b21b5eb8 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -97,6 +97,9 @@ static int set_max_cstate(struct dmi_system_id *id)
 /* Actually this shouldn't be __cpuinitdata, would be better to fix the
    callers to only run once -AK */
 static struct dmi_system_id __cpuinitdata processor_power_dmi_table[] = {
+	{ set_max_cstate, "IBM ThinkPad R40e", {
+	  DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
+	  DMI_MATCH(DMI_BIOS_VERSION,"1SET70WW")}, (void *)1},
 	{ set_max_cstate, "IBM ThinkPad R40e", {
 	  DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
 	  DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW")}, (void *)1},
@@ -365,7 +368,9 @@ static void acpi_processor_idle(void)
 		t1 = inl(acpi_fadt.xpm_tmr_blk.address);
 		/* Invoke C2 */
 		inb(cx->address);
-		/* Dummy op - must do something useless after P_LVL2 read */
+		/* Dummy wait op - must do something useless after P_LVL2 read
+		   because chipsets cannot guarantee that STPCLK# signal
+		   gets asserted in time to freeze execution properly. */
 		t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 		/* Get end time (ticks) */
 		t2 = inl(acpi_fadt.xpm_tmr_blk.address);
@@ -403,7 +408,7 @@ static void acpi_processor_idle(void)
 		t1 = inl(acpi_fadt.xpm_tmr_blk.address);
 		/* Invoke C3 */
 		inb(cx->address);
-		/* Dummy op - must do something useless after P_LVL3 read */
+		/* Dummy wait op (see above) */
 		t2 = inl(acpi_fadt.xpm_tmr_blk.address);
 		/* Get end time (ticks) */
 		t2 = inl(acpi_fadt.xpm_tmr_blk.address);