thermal: intel: pch: improve the cooling delay log

Previously, during suspend, intel_pch_thermal driver logs for every
cooling iteration, about the current PCH temperature and number of cooling
iterations that have been tried, like below

[  100.955526] intel_pch_thermal 0000:00:14.2: CPU-PCH current temp [53C] higher than the threshold temp [50C], sleep 1 times for 100 ms duration
[  101.064156] intel_pch_thermal 0000:00:14.2: CPU-PCH current temp [53C] higher than the threshold temp [50C], sleep 2 times for 100 ms duration

After changing the default delay_cnt to 600, in practice, it is common to
see tens of the above messages if the system is suspended when PCH
overheats. Thus, change this log message from dev_warn to dev_dbg because
it is only useful when we want to check the temperature trend.

At the same time, there is always a one-line message given by the driver
with the patch applied, with below four possibilities.

1. PCH is cool, no cooling delay needed
[ 1791.902853] intel_pch_thermal 0000:00:12.0: CPU-PCH is cool [48C]

2. PCH overheats and becomes cool after the cooling delays
[ 1475.511617] intel_pch_thermal 0000:00:12.0: CPU-PCH is cool [49C] after 30700 ms delay

3. PCH still overheats after the overall cooling timeout
[ 2250.157487] intel_pch_thermal 0000:00:12.0: CPU-PCH is hot [60C] after 60000 ms delay. S0ix might fail

4. PCH aborts cooling because of wakeup event detected during the delay
[ 1933.639509] intel_pch_thermal 0000:00:12.0: Wakeup event detected, abort cooling

Signed-off-by: Zhang Rui <[email protected]>
Tested-by: Sumeet Pawnikar <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>

drivers/thermal/intel/intel_pch_thermal.c

@@ -197,7 +197,7 @@ static int pch_wpt_get_temp(struct pch_thermal_device *ptd, int *temp)
 static int pch_wpt_suspend(struct pch_thermal_device *ptd)
 {
 	u8 tsel;
-	int pch_delay_cnt = 1;
+	int pch_delay_cnt = 0;
 	u16 pch_thr_temp, pch_cur_temp;
 
 	/* Shutdown the thermal sensor if it is not enabled by BIOS */
@@ -233,29 +233,38 @@ static int pch_wpt_suspend(struct pch_thermal_device *ptd)
 	 * temperature stays above threshold, notify the warning message
 	 * which helps to indentify the reason why S0ix entry was rejected.
 	 */
-	while (pch_delay_cnt <= delay_cnt) {
+	while (pch_delay_cnt < delay_cnt) {
 		if (pch_cur_temp < pch_thr_temp)
 			break;
 
-		if (pm_wakeup_pending())
-			break;
+		if (pm_wakeup_pending()) {
+			dev_warn(&ptd->pdev->dev, "Wakeup event detected, abort cooling\n");
+			return 0;
+		}
 
-		dev_warn(&ptd->pdev->dev,
+		pch_delay_cnt++;
+		dev_dbg(&ptd->pdev->dev,
 			"CPU-PCH current temp [%dC] higher than the threshold temp [%dC], sleep %d times for %d ms duration\n",
 			pch_cur_temp, pch_thr_temp, pch_delay_cnt, delay_timeout);
 		msleep(delay_timeout);
 		/* Read the PCH current temperature for next cycle. */
 		pch_cur_temp = GET_PCH_TEMP(WPT_TEMP_TSR & readw(ptd->hw_base + WPT_TEMP));
-		pch_delay_cnt++;
 	}
 
 	if (pch_cur_temp >= pch_thr_temp)
 		dev_warn(&ptd->pdev->dev,
-			"CPU-PCH is hot [%dC] even after delay, continue to suspend. S0ix might fail\n",
-			pch_cur_temp);
-	else
-		dev_info(&ptd->pdev->dev,
-			"CPU-PCH is cool [%dC], continue to suspend\n", pch_cur_temp);
+			"CPU-PCH is hot [%dC] after %d ms delay. S0ix might fail\n",
+			pch_cur_temp, pch_delay_cnt * delay_timeout);
+	else {
+		if (pch_delay_cnt)
+			dev_info(&ptd->pdev->dev,
+				"CPU-PCH is cool [%dC] after %d ms delay\n",
+				pch_cur_temp, pch_delay_cnt * delay_timeout);
+		else
+			dev_info(&ptd->pdev->dev,
+				"CPU-PCH is cool [%dC]\n",
+				pch_cur_temp);
+	}
 
 	return 0;
 }