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<b><a class="bz_bug_link
bz_status_NEW "
title="NEW - [BYT] No picture on DSI display after DRM loads on Teclast X80H tablet"
href="https://bugs.freedesktop.org/show_bug.cgi?id=96996#c1">Comment # 1</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW - [BYT] No picture on DSI display after DRM loads on Teclast X80H tablet"
href="https://bugs.freedesktop.org/show_bug.cgi?id=96996">bug 96996</a>
from <span class="vcard"><a class="email" href="mailto:laszlo.fiat@gmail.com" title="Laszlo Fiat <laszlo.fiat@gmail.com>"> <span class="fn">Laszlo Fiat</span></a>
</span></b>
<pre>I've had this bug open as <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED DUPLICATE - [BYT] Blank screen on DSI display after drm loads on Teclast X80h tablet"
href="show_bug.cgi?id=93799">BUG 93799</a>, then I added it as a duplicate of BUG
90469, which is the same issue on a different hardware, but that bug was tested
on its original hardware, and got closed.
As I wrote in <a class="bz_bug_link
bz_status_CLOSED bz_closed"
title="CLOSED WORKSFORME - [BYT dsi] WARNING: CPU: 3 PID: 265 at drivers/gpu/drm/drm_irq.c:1130 drm_wait_one_vblank+0x177/0x180()"
href="show_bug.cgi?id=90469#c51">BUG 90469 Comment 51</a>, the kernels between linux-next-20151012 to
linux-next-20151119 actually worked, there were some red or purple screen for a
second, but then the DSI display worked properly.
I found out that for later kernels I needed to add i915.fastboot=1 to have the
display working, like 4.6.0-rc4.
But something went wrong again, because it doesn't work even with
i915.fastboot=1 with newer kernels (I first detected this on 20160517 with
intel-drm-nightly)
With kernels, where the DSI display doesn't work, there are warnings in the
dmesg. In the latest dmesg I get:
[ 8.592431] WARNING: CPU: 3 PID: 59 at
drivers/gpu/drm/i915/intel_display.c:13590
intel_atomic_commit_tail+0x104b/0x1050 [i915]
[ 8.592435] pipe A vblank wait timed out</pre>
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