linux-kernel - [PATCH 3.14 52/64] thermal: step

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20150603063930.710988617@linuxfoundation.org>
Date:	Wed,  3 Jun 2015 20:43:20 +0900
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org, stable <stable@...r.kernel.org>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jean Delvare <jdelvare@...e.de>, Peter Feuerer <peter@...e.net>
Subject: [PATCH 3.14 52/64] thermal: step_wise: Revert optimization

3.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jean Delvare <jdelvare@...e.de>

Commit 178c2490b99f898efc06d1ad75cadc84f13021a6 ("thermal: step_wise:
cdev only needs update on a new target state") broke driver acerhdf.
That driver abused the step_wise thermal governor until the bang_bang
governor was available, and the optimization broke this usage model.

Kernels v3.12 to v3.18 are affected. In v3.19 the acerhdf driver was
switched to the bang_bang governor and that solved the problem.

For kernels v3.12 to v3.17, the bang_bang governor isn't available
yet so the easiest fix is to revert the optimization.

Signed-off-by: Jean Delvare <jdelvare@...e.de>
Reported-by: Dieter Jurzitza (https://bugzilla.opensuse.org/show_bug.cgi?id=925961)
Tested-by: Peter Feuerer <peter@...e.net>
Tested-by: Dieter Jurzitza
---
Please consider this patch for stable kernel branches from v3.12 to v3.17.

If anyone cares about v3.18, I think a better fix would be to backport
commit 48c8dd64345ba2a8c41556095c7adacb1c8af7c1 ("acerhdf: Use bang-bang
thermal governor") but it's too big for stable, so it's left to
distributions. So maybe this fix should make it into v3.18 stable as
well - I'll let whoever maintains that branch decide.

 drivers/thermal/step_wise.c |    3 ---
 1 file changed, 3 deletions(-)

--- a/drivers/thermal/step_wise.c
+++ b/drivers/thermal/step_wise.c
@@ -146,9 +146,6 @@ static void thermal_zone_trip_update(str
 		dev_dbg(&instance->cdev->device, "old_target=%d, target=%d\n",
 					old_target, (int)instance->target);

-		if (old_target == instance->target)
-			continue;
-
 		/* Activate a passive thermal instance */
 		if (old_target == THERMAL_NO_TARGET &&
 			instance->target != THERMAL_NO_TARGET)

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/