search for: bump_period

https://bugs.freedesktop.org/show_bug.cgi?id=65554 Priority: medium Bug ID: 65554 Assignee: nouveau at lists.freedesktop.org Summary: CPU lock with nouveau_fan_update QA Contact: xorg-team at lists.x.org Severity: major Classification: Unclassified OS: Linux (All) Reporter: ddamienn at gmail.com

Hello there, [linux-4.13/drivers/gpu/drm/nouveau/nvkm/subdev/therm/fan.c:93]: (warning) Opposite inner 'if' condition leads to a dead code block. Source code is if (target != duty) { u16 bump_period = fan->bios.bump_period; u16 slow_down_period = fan->bios.slow_down_period; u64 delay; if (duty > target) delay = slow_down_period; else if (duty == target) delay = min(bump_period, slow_down_period) ; Last if can never be true, so...

...100644 --- a/drivers/gpu/drm/nouveau/nvkm/subdev/therm/fan.c +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/therm/fan.c @@ -90,8 +90,6 @@ nvkm_fan_update(struct nvkm_fan *fan, bool immediate, int target) if (duty > target) delay = slow_down_period; - else if (duty == target) - delay = min(bump_period, slow_down_period) ; else delay = bump_period; -- 2.39.2

...ers/gpu/drm/nouveau/core/subdev/bios/therm.c @@ -184,7 +184,8 @@ nvbios_therm_fan_parse(struct nouveau_bios *bios, cur_trip->fan_duty = value; break; case 0x26: - fan->pwm_freq = value; + if (!fan->pwm_freq) + fan->pwm_freq = value; break; case 0x3b: fan->bump_period = value; -- 1.8.4

...case 0x26: > - fan->pwm_freq = value; > + if (!fan->pwm_freq) > + fan->pwm_freq = value; > break; > case 0x3b: > fan->bump_period = value; > -- > 1.8.4 > > _______________________________________________ > Nouveau mailing list > Nouveau at lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/nouveau

From: Martin Peres <martin.peres at labri.fr> This should fix a deadlock that has been reported to us where fan_update() would hold the fan lock and try to grab the alarm_program_lock to reschedule an update. On an other CPU, the alarm_program_lock would have been taken before calling fan_update(), leading to a deadlock. We should Cc: <stable at vger.kernel.org> # 3.9+ Reported-by: