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<body><span class="vcard"><a class="email" href="mailto:andreatclist@gmail.com" title="Andrea <andreatclist@gmail.com>"> <span class="fn">Andrea</span></a>
</span> changed
<a class="bz_bug_link
bz_status_NEW "
title="NEW - [regression, bisected] [i915] setting initial watermarks on gen 7 IVYBRIDGE causes blank lines on monitor"
href="https://bugs.freedesktop.org/show_bug.cgi?id=109477">bug 109477</a>
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<th>What</th>
<th>Removed</th>
<th>Added</th>
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<td style="text-align:right;">Status</td>
<td>NEEDINFO
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<td>NEW
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<b><a class="bz_bug_link
bz_status_NEW "
title="NEW - [regression, bisected] [i915] setting initial watermarks on gen 7 IVYBRIDGE causes blank lines on monitor"
href="https://bugs.freedesktop.org/show_bug.cgi?id=109477#c7">Comment # 7</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW - [regression, bisected] [i915] setting initial watermarks on gen 7 IVYBRIDGE causes blank lines on monitor"
href="https://bugs.freedesktop.org/show_bug.cgi?id=109477">bug 109477</a>
from <span class="vcard"><a class="email" href="mailto:andreatclist@gmail.com" title="Andrea <andreatclist@gmail.com>"> <span class="fn">Andrea</span></a>
</span></b>
<pre>(In reply to Ville Syrjala from <a href="show_bug.cgi?id=109477#c6">comment #6</a>)
<span class="quote">> All the numbers look very much correct :/
>
> Does the corruption go away if you start X (or whatever) that enables the
> hardware cursor? The watermark dumps at least seemed to be w/o the cursor.</span >
The corruption is present since boot-time, and stays there when the X starts.
Sometimes it disappears (e.g., in response to a window/desktop switch), but in
a non-deterministic way and the corruption comes back later.
<span class="quote">> I see the BIOS is pretty old. Can you try to update it?</span >
I will try in the next days, but from a first look it seems all updates require
Windows (which I've not on this system).
<span class="quote">> Let's also try to figure out which watermark level is the problem.
> Please do these tests with drm-tip because it might not work with an older
> kernel.
>
> First let's rule out LP3:
> # echo '12 4 16 0' > /sys/kernel/debug/dri/0/i915_pri_wm_latency
> # echo '12 4 16 0' > /sys/kernel/debug/dri/0/i915_cur_wm_latency
> $ xset dpms force off ; xset dpms force on
> Still corrupted?</span >
Yes
<span class="quote">> Then LP2:
> # echo '12 4 0 0' > /sys/kernel/debug/dri/0/i915_pri_wm_latency
> # echo '12 4 0 0' > /sys/kernel/debug/dri/0/i915_cur_wm_latency
> $ xset dpms force off ; xset dpms force on
> Still corrupted?</span >
Yes
<span class="quote">> And finally LP1:
> # echo '12 0 0 0' > /sys/kernel/debug/dri/0/i915_pri_wm_latency
> # echo '12 0 0 0' > /sys/kernel/debug/dri/0/i915_cur_wm_latency
> $ xset dpms force off ; xset dpms force on
> Still corrupted?</span >
No, the corruption is gone. Switching windows, desktops, focus etc seems to
work fine. And it doesn't re-appear after > 10 mins.</pre>
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