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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - No Screen Updates on fbcon with PSR enabled on Thinkpad T450s (Broadwell), Linux 5.1.5"
href="https://bugs.freedesktop.org/show_bug.cgi?id=110799">110799</a>
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<th>Summary</th>
<td>No Screen Updates on fbcon with PSR enabled on Thinkpad T450s (Broadwell), Linux 5.1.5
</td>
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<th>Product</th>
<td>DRI
</td>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>x86-64 (AMD64)
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<th>OS</th>
<td>Linux (All)
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>medium
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<th>Component</th>
<td>DRM/Intel
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<th>Assignee</th>
<td>intel-gfx-bugs@lists.freedesktop.org
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<th>Reporter</th>
<td>trohwer85@gmail.com
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<th>QA Contact</th>
<td>intel-gfx-bugs@lists.freedesktop.org
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<th>CC</th>
<td>intel-gfx-bugs@lists.freedesktop.org
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<pre>I enabled PSR on my Thinkpad T450s (Broadwell) with Linux 5.1.5. This works
fine under X, but I get no screen updates on the fbcon (typing etc. does show
no change on screen, only switching to/back X makes the stuff visible).
Without PSR, the fbcon works fine.
I investigated a bit and identified this code in drm/i915/intel_psr.c
(printk added by me) to exit PSR on fbcon dirty calls:
/* By definition flush = invalidate + flush */
if (frontbuffer_bits) {
/*
* Display WA #0884: all
* This documented WA for bxt can be safely applied
* broadly so we can force HW tracking to exit PSR
* instead of disabling and re-enabling.
* Workaround tells us to write 0 to CUR_SURFLIVE_A,
* but it makes more sense write to the current active
* pipe.
*/
printk(KERN_DEBUG "WA\n");
I915_WRITE(CURSURFLIVE(dev_priv->psr.pipe), 0);
}
The code is called for fbcon changes, but as stated, it does not seem to have
the effect of exiting PSR on my hardware.</pre>
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