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

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Message-ID: <CAKMK7uHh4mDgz4G8VAy7G7iMM13sxR-aqMgSdDNP8QWd3P8GPQ@mail.gmail.com>
Date:   Sun, 7 May 2017 19:56:29 +0200
From:   Daniel Vetter <daniel@...ll.ch>
To:     Jens Axboe <axboe@...nel.dk>
Cc:     "Syrjala, Ville" <ville.syrjala@...ux.intel.com>,
        intel-gfx <intel-gfx@...ts.freedesktop.org>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Jani Nikula <jani.nikula@...ux.intel.com>,
        Dave Airlie <airlied@...hat.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>
Subject: Re: [PATCH] drm/i915: Make vblank evade warnings optional

On Sun, May 7, 2017 at 7:46 PM, Jens Axboe <axboe@...nel.dk> wrote:
> On 05/07/2017 11:12 AM, ville.syrjala@...ux.intel.com wrote:
>> From: Ville Syrjälä <ville.syrjala@...ux.intel.com>
>>
>> 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.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch