i915: screen flicker

[Jani Nikula]

On Wed, 27 Apr 2016, Mihai Donțu <mihai.dontu at gmail.com> wrote:
> On Wed, 27 Apr 2016 20:36:13 +0300 Mihai Donțu wrote:
>> On Wed, 27 Apr 2016 08:28:20 -0700 Rodrigo Vivi wrote:
>> > Hi Mihai,
>> > 
>> > What platform do you have? HSW or BDW?  
>> 
>> I have an i7, Haswell CPU.
>> 
>> > If you don't know please provide lspci -nn  
>> 
>> I have attached the output of lspci, just in case. :-)
>> 
>> > What happens if you boot with i915.enable_psr=2?  
>> 
>> I'll try now.
>
> The behaviour is worse now. The screen flickers every couple of seconds.

Another report, please move the discussion there:

https://bugs.freedesktop.org/show_bug.cgi?id=95176

Thanks,
Jani.

>
>> > 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");
>> >   
>> 
>> I applied your patch and booted with enable_psr=-1
>> 
>> [    0.763651] [drm:intel_psr_init] *ERROR* PSR: VBT recommends link_standby 0, using 0

-- 
Jani Nikula, Intel Open Source Technology Center