From 44241628bb207ec211bebd156aaf69470d90c209 Mon Sep 17 00:00:00 2001 From: Andrea Arcangeli <aarcange@redhat.com> Date: Thu, 1 Oct 2015 15:37:16 -0700 Subject: [PATCH] thermal: avoid division by zero in power allocator During boot I get a div by zero Oops regression starting in v4.3-rc3. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Javi Merino <javi.merino@arm.com> Cc: Zhang Rui <rui.zhang@intel.com> Cc: Eduardo Valentin <edubezval@gmail.com> Cc: Daniel Kurtz <djkurtz@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> --- drivers/thermal/power_allocator.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/thermal/power_allocator.c b/drivers/thermal/power_allocator.c index 7ff96270c933b1..e570ff084add5b 100644 --- a/drivers/thermal/power_allocator.c +++ b/drivers/thermal/power_allocator.c @@ -144,6 +144,16 @@ static void estimate_pid_constants(struct thermal_zone_device *tz, switch_on_temp = 0; temperature_threshold = control_temp - switch_on_temp; + /* + * estimate_pid_constants() tries to find appropriate default + * values for thermal zones that don't provide them. If a + * system integrator has configured a thermal zone with two + * passive trip points at the same temperature, that person + * hasn't put any effort to set up the thermal zone properly + * so just give up. + */ + if (!temperature_threshold) + return; if (!tz->tzp->k_po || force) tz->tzp->k_po = int_to_frac(sustainable_power) / -- GitLab