From: Jani Nikula <jani.nikula@linux.intel.com>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Airlie <airlied@linux.ie>,
intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH 1/1] drm: i915: don't use OpRegion for XPS 13 IvyBridge
Date: Mon, 29 Aug 2016 18:08:39 +0300 [thread overview]
Message-ID: <874m63ipe0.fsf@intel.com> (raw)
In-Reply-To: <20160829133241.l2txb2rpnahlfufb@redhat.com>
On Mon, 29 Aug 2016, Andrea Arcangeli <aarcange@redhat.com> wrote:
> On Mon, Aug 29, 2016 at 10:24:38AM +0300, Jani Nikula wrote:
>> If it's an Iybridge, there's no low vswing, and that explanation is
>> false. You can verify by trying i915.edp_vswing=1 or i915.edp_vswing=2
>> on an unpatched kernel.
>
> What I should look for when trying those two settings? Will they
> successfully fix my problem with intel_backlight with upstream 4.8-rc?
>
> I thought it had to be the same issue as on skylake as I get the
> backlight flikering at low frequency but getting brighter and darker
> in a cycle lasting a few seconds and I thought there couldn't be too
> many other random bugs that ends up with the same side effect.
Your Ivybridge does not have low voltage swing *and* low voltage swing
has nothing to do with the backlight. The regressing commit may be the
same for you, but the failure mode appears to be completely different.
BR,
Jani.
--
Jani Nikula, Intel Open Source Technology Center
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Intel-gfx mailing list
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next prev parent reply other threads:[~2016-08-29 15:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1472398126-1095-1-git-send-email-aarcange@redhat.com>
[not found] ` <1472398126-1095-2-git-send-email-aarcange@redhat.com>
2016-08-29 7:24 ` [PATCH 1/1] drm: i915: don't use OpRegion for XPS 13 IvyBridge Jani Nikula
2016-08-29 13:32 ` Andrea Arcangeli
2016-08-29 15:08 ` Jani Nikula [this message]
2016-08-29 18:48 ` Andrea Arcangeli
2016-08-30 6:54 ` Martin van Es
2016-08-30 8:13 ` Jani Nikula
2016-08-30 9:13 ` Martin van Es
2016-08-30 7:25 ` Jani Nikula
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