linux-kernel - Re: Bad flicker on skylake HQD due to code in the 4.7 merge window

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Date:	Tue, 31 May 2016 06:33:58 -0700
From:	James Bottomley <James.Bottomley@...senPartnership.com>
To:	Jani Nikula <jani.nikula@...ux.intel.com>,
	intel-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org
Cc:	linux-kernel <linux-kernel@...r.kernel.org>,
	Rodrigo Vivi <rodrigo.vivi@...el.com>
Subject: Re: Bad flicker on skylake HQD due to code in the 4.7 merge window

On Tue, 2016-05-31 at 10:51 +0300, Jani Nikula wrote:
> On Mon, 30 May 2016, James Bottomley <
> James.Bottomley@...senPartnership.com> wrote:
> > I've tested a pristine 4.6.0 system, so it's definitely something
> > that
> > went in during the merge window.  The flicker isn't continuous,
> > it's
> > periodic, with an interval of something like 2-5 seconds.  It looks
> > like an old analogue TV going out of sync and then resyncing.  I've
> > attached the dmesg and X.org log below just in case they can help. 
> >  I
> > might be able to bisect this next week, but, unfortunately, this is
> > my
> > current laptop and I'm travelling this week.
> 
> Please try i915.enable_psr=0 module parameter.

Makes no discernable difference.  Current parameter settings are:

disable_display: N
disable_power_well: 1
edp_vswing: 0
enable_cmd_parser: 1
enable_dc: -1
enable_dp_mst: Y
enable_execlists: 1
enable_fbc: -1
enable_guc_submission: N
enable_hangcheck: Y
enable_ips: 1
enable_ppgtt: 3
enable_psr: 0
enable_rc6: 1
fastboot: N
guc_log_level: -1
inject_load_failure: 0
invert_brightness: 0
load_detect_test: N
lvds_channel_mode: 0
lvds_use_ssc: -1
mmio_debug: 0
modeset: -1
nuclear_pageflip: N
panel_ignore_lid: 1
prefault_disable: N
preliminary_hw_support: 1
reset: Y
semaphores: -1
use_mmio_flip: 0
vbt_sdvo_panel_type: -1
verbose_state_checks: Y

James