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<b><a class="bz_bug_link
bz_status_NEEDINFO "
title="NEEDINFO - i915.fastboot=1 is broken on Thinkpad S1 Yoga (Haswell)"
href="https://bugs.freedesktop.org/show_bug.cgi?id=108773#c22">Comment # 22</a>
on <a class="bz_bug_link
bz_status_NEEDINFO "
title="NEEDINFO - i915.fastboot=1 is broken on Thinkpad S1 Yoga (Haswell)"
href="https://bugs.freedesktop.org/show_bug.cgi?id=108773">bug 108773</a>
from <span class="vcard"><a class="email" href="mailto:ville.syrjala@linux.intel.com" title="Ville Syrjala <ville.syrjala@linux.intel.com>"> <span class="fn">Ville Syrjala</span></a>
</span></b>
<pre>Nothing remarkable in the backlight setup.
Hmm. Looks like the BIOS is using SPLL for eDP. We do seem to leave that
correctly enabled, but maybe we're turning off its reference by mistake.
It is using the SSC reference by the looks of it, but the question which one.
What does 'intel_reg read 0x42004' say?
Assuming it's using the PCH SSC reference this might help:
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -15342,7 +15342,7 @@ static void intel_setup_outputs(struct drm_i915_private
*dev_priv)
intel_encoder_clones(encoder);
}
- intel_init_pch_refclk(dev_priv);
+ //intel_init_pch_refclk(dev_priv);
drm_helper_move_panel_connectors_to_head(&dev_priv->drm);
}</pre>
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