Re: [PATCH] drm/i915: Make vblank evade warnings optional

From: Jens Axboe
Date: Sun May 07 2017 - 21:52:32 EST

On 05/07/2017 11:56 AM, Daniel Vetter wrote:
> On Sun, May 7, 2017 at 7:46 PM, Jens Axboe <axboe@xxxxxxxxx> wrote:
>> On 05/07/2017 11:12 AM, ville.syrjala@xxxxxxxxxxxxxxx wrote:
>>> From: Ville SyrjÃlà <ville.syrjala@xxxxxxxxxxxxxxx>
>>> Add a new Kconfig option to enable/disable the extra warnings
>>> from the vblank evade code. For now we'll keep the warning
>>> about an actually missed vblank always enabled as that can have
>>> an actual user visible impact. But if we miss the deadline
>>> othrwise there's no real need to bother the user with that.
>>> We'll want these warnings enabled during development however
>>> so that we can catch regressions.
>>> Based on the reports it looks like this is still very easy
>>> to hit on SKL, so we have more work ahead of us to optimize
>>> the crtiical section further.
>> Shouldn't it just be a debug printk or something instead, so that normal
>> people don't see it, but the folks that turn on debugging can get the
>> info they need? Seems silly to add a kconfig option for this.
> I guess we could keep it as debug for users, but we want to make this
> a hard failure on our CI machines. Kconfig knob is the easiest to roll
> out to all machines.

Wouldn't a module parameter be more useful then, as an opt-in
to catch these violations.

Nobody is going to know wtf to set this kconfig option to.

Jens Axboe