<div dir="ltr"><div>Note:</div><div>The system does not hang. I can ssh into the system and execute commands successfully.</div><div><br></div>Also, external displays work fine. I have currently attached the laptop to a HDMI display, and the laptop continues to send video output to the HDMI display. So, I can continue to use it that way. It is only the LVDS panel that does not display anything.<div> <br></div><div>Here are the steps I have taken to try and fix the problem so far:</div><div><br></div><div><span id="docs-internal-guid-bbd1e82f-06d1-536d-02ce-66afda72177a"><p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"> <span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">Tried troubleshooting steps here: </span><a href="https://wiki.archlinux.org/index.php/Backlight" style="text-decoration:none"><span style="font-size:15px;font-family:Arial;background-color:transparent;text-decoration:underline;vertical-align:baseline;white-space:pre-wrap">https://wiki.archlinux.org/index.php/Backlight</span></a><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap"> to no avail.</span></p> <br><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap"></span><br><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap"></span><p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"> <span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">acpi_osi kernel parameter - BIOS may query the OS to find out which OS it is (Windows, Linux, etc.) and appropriately disable/enable certain features to ensure compatibility. When BIOS asks Linux if it is a Linux system, by default Linux ignores the query (so that all features are exposed). acpi_osi allows users to override that behaviour. The value for acpi_osi will be given to the BIOS by Linux when BIOS queries the OS.</span></p> <br><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap"></span><p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"> <span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">Tried following kernel parameters:</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">video.use_native_nacklight=1</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">acpi_osi=Linux acpi_backlight=vendor</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">acpi_backlight=legacy</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">systemd.restore_state=0</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">acpi_osi=Linux</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">acpi_osi=Windows</span></p> <br><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap"></span><p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"> <span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">Did not affect outcome.</span></p> <br><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap"></span><p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"> <span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">Tried using pm-suspend with following quirks:</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">quirk-radeon-off</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">quirk-dpms-on</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">quirk-s3-bios</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">quirk-vbe-post</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">quirk-dpms-suspend</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">quirk-s3-mode</span></p> <br><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap"></span><p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"> <span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">Did not affect outcome.</span></p> <br><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap"></span><p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"> <span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">Stored following code in /etc/pm/sleep.d/00displaywakeup :</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">#!/bin/sh</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">#</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">case "$1" in</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap"> suspend)</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap"> ;;</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap"> resume)</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap"> sleep 5</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap"> vbetool dpms off</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap"> vbetool dpms on</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap"> ;;</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap"> *) exit $NA</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap"> ;;</span></p> <p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">esac</span></p> <br><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap"></span><p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"> <span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">Did not affect outcome.</span></p> <br><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap"></span><p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"> <span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">Executed: radeontool light on</span></p> <br><span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap"></span><p dir="ltr" style="line-height:1.15;margin-top:0pt;margin-bottom:0pt"> <span style="font-size:15px;font-family:Arial;color:rgb(0,0,0);background-color:transparent;vertical-align:baseline;white-space:pre-wrap">Did not affect outcome.</span></p> </span></div><div><br></div><div>- Sandeep</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, Mar 27, 2014 at 8:34 PM, Sandeep <span dir="ltr"><<a href="mailto:sandy.8925@gmail.com" target="_blank">sandy.8925@gmail.com</a>></span> wrote:<br> <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>I am currently facing a problem on my laptop (an ASUS K53TA). The LVDS display is blank (no backlight) after suspending and resuming.<br> </div><div><br></div><div>On Windows, using AMD's Catalyst driver the display is still active after suspend and resume, so the problem occurs only in Linux.</div> <div><br></div><div>I am running Arch Linux 64 bit , with Linux kernel 3.13.6. I have filed a bug report already: <a href="https://bugs.freedesktop.org/show_bug.cgi?id=42960" target="_blank">https://bugs.freedesktop.org/show_bug.cgi?id=42960</a></div> <div><br></div><div>I have faced this problem since Linux kernel 3.2 , so as far as I know it is not a regression. </div><div><br></div><div>I had used AMD's Catalyst drivers for some time, and the same problem had occurred with those drivers as well, but the problem was fixed in later versions of the Catalyst driver.</div> <div><br></div><div>I want to figure out why this problem occurs and find a permanent fix. </div><div><br></div><div>Could someone please tell me if the GPU driver is the only code responsible for bringing up the display, or are other parts of the kernel involved as well? How would I begin to debug this issue?</div> <div><br></div><div>Thanks in advance,</div><div>Sandeep</div></div> </blockquote></div><br></div>