i915: screen flicker

[Rodrigo Vivi]

Hi Mihai,

What platform do you have? HSW or BDW?
If you don't know please provide lspci -nn

What happens if you boot with i915.enable_psr=2?

In case it helps, could you please boot with default
i915.enable_psr=-1 appying this patch to your kernel to know what your
VBT recommends:
diff --git a/drivers/gpu/drm/i915/intel_psr.c
b/drivers/gpu/drm/i915/intel_psr.c
index c3abae4..68bc405 100644
--- a/drivers/gpu/drm/i915/intel_psr.c
+++ b/drivers/gpu/drm/i915/intel_psr.c
@@ -798,6 +798,8 @@ void intel_psr_init(struct drm_device *dev)
                /* For new platforms let's respect VBT back again */
                dev_priv->psr.link_standby =
dev_priv->vbt.psr.full_link;

+       DRM_ERROR("PSR: VBT recommends link_standby %d, using %d\n",
dev_priv->vbt.psr.full_link, dev_priv->psr.link_standby);
+
        /* Override link_standby x link_off defaults */
        if (i915.enable_psr == 2 && !dev_priv->psr.link_standby) {
                DRM_DEBUG_KMS("PSR: Forcing link standby\n");

//Thanks
//Rodrigo.

On Wed, Apr 27, 2016 at 3:35 AM, Jani Nikula
<jani.nikula at linux.intel.com> wrote:
> On Wed, 27 Apr 2016, Mihai Donțu <mihai.dontu at gmail.com> wrote:
>> On Wed, 27 Apr 2016 10:09:32 +0300 Jani Nikula wrote:
>>> On Wed, 27 Apr 2016, Mihai Donțu wrote:
>>> > I noticed that since I started using 4.6.0-rcX, my screen flickers once
>>> > or twice after I stop using my laptop for ~1min or so. Given the
>>> > behavior, my prime suspect is the PSR feature that you have announced
>>> > for this release:
>>> >
>>> >   http://blog.ffwll.ch/2016/03/neat-drmi915-stuff-for-46.html
>>> >
>>> > Is 'enable_psr' the right knob to use to turn this feature off and see
>>> > if my suspicions are correct? Or is there a patch floating around that
>>> > I can test?
>>>
>>> i915.enable_psr=0 is the one to try, yes.
>>
>> I can confirm that with PSR off, the flicker goes away.
>
> Please file a bug at [1] and assign to Rodrigo (Cc'd).
>
> BR,
> Jani.
>
> [1] https://bugs.freedesktop.org/enter_bug.cgi?product=DRI&component=DRM/Intel
>
>
> --
> Jani Nikula, Intel Open Source Technology Center



-- 
Rodrigo Vivi
Blog: http://blog.vivi.eng.br