On Thursday 23 June 2016 05:57 PM, Rafael J. Wysocki wrote:
On Wed, Jun 22, 2016 at 7:06 AM, Eduardo Valentin <edubezval@xxxxxxxxx> wrote:
Because several drivers do the following pattern:
.set_mode()
...
local_data->mode = new_mode;
thermal_zone_device_update(tz);
makes sense to simply do the thermal_zone_device_update()
in thermal core, after setting the new mode.
Also, this patch also remove deadlocks on drivers that
call thermal_zone_device_update() on .set_mode(),
as .set_mode() is now called always with tz->lock held.
To me, this part of the patch is way more important than the
optimization mentioned before.
Apparently, the problem is that drivers deadlock, because the
thermal_zone_device_update() invoked from ->set_mode() is called under
tz->lock.
So to address that problem you make the core call
thermal_zone_device_update() after ->set_mode() outside of tz->lock
and the drivers don't have to do it any more.
Is that correct?
Rafael,
On my set up, mode_store locks tz->lock and eventually ends up calling
of_thermal_set_mode before releasing tz->lock which again tries to lock
tz->lock and ends up in a deadlock.
http://pastebin.ubuntu.com/17687601/
Regards,
Keerthy
Thanks,
Rafael
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