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<b><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [845g regression] No output on LVDS"
href="https://bugs.freedesktop.org/show_bug.cgi?id=66516#c3">Comment # 3</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [845g regression] No output on LVDS"
href="https://bugs.freedesktop.org/show_bug.cgi?id=66516">bug 66516</a>
from <span class="vcard"><a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> <span class="fn">Chris Wilson</span></a>
</span></b>
<pre>b5ea2d5681522f1b8ef886b5ac039903bf1d39fe is the first bad commit
commit b5ea2d5681522f1b8ef886b5ac039903bf1d39fe
Author: Daniel Vetter <<a href="mailto:daniel.vetter@ffwll.ch">daniel.vetter@ffwll.ch</a>>
Date: Thu Jun 27 17:52:15 2013 +0200
drm/i915: fix hpd interrupt register locking
Our interrupt handler (in hardirq context) could race with the timer
(in softirq context), hence we need to hold the spinlock around the
call to ->hdp_irq_setup in intel_hpd_irq_handler, too.
But as an optimization (and more so to clarify things) we don't need
to do the irqsave/restore dance in the hardirq context.
Note also that on ilk+ the race isn't just against the hotplug
reenable timer, but also against the fifo underrun reporting. That one
also modifies the SDEIMR register (again protected by the same
dev_priv->irq_lock).
To lock things down again sprinkle a assert_spin_locked. But exclude
the functions touching SDEIMR for now, I want to extract them all into
a new helper function (like we do already for pipestate, display
interrupts and all the various gt interrupts).
v2: Add the missing 't' Egbert spotted in a comment.
v3: Actually fix the right misspelled comment (Paulo).
Cc: Egbert Eich <<a href="mailto:eich@suse.de">eich@suse.de</a>>
Reviewed-by: Paulo Zanoni <<a href="mailto:paulo.r.zanoni@intel.com">paulo.r.zanoni@intel.com</a>>
Signed-off-by: Daniel Vetter <<a href="mailto:daniel.vetter@ffwll.ch">daniel.vetter@ffwll.ch</a>></pre>
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