<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO - [GLK DSI] Black screen after grub - Ubuntu 18.04 - kernel latest tip 21.11.2018" href="https://bugs.freedesktop.org/show_bug.cgi?id=108826#c114">Comment # 114</a> on <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO - [GLK DSI] Black screen after grub - Ubuntu 18.04 - kernel latest tip 21.11.2018" href="https://bugs.freedesktop.org/show_bug.cgi?id=108826">bug 108826</a> from <a class="email" href="mailto:stanislav.lisovskiy@intel.com" title="Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>"> Stanislav Lisovskiy</a> <pre>There seem to be some issue with gpio pins used in vbt sequences used for Microtech Etab. I see that backlight gpio pin index 4 works as supposed, while accessing others actually breaks the display. That explains also why initially it did work without geminilake_pinctrl - it simply couldn't access those, which was visible in the log. I confirmed this also by adding small hack to mipi_exec_gpio function so that it doesn't touch pins 3, 6 which used for power_on and reset respectively. Then my etab works with geminilake_pinctrl, also I can see the backlight switching on/off during suspend/resume. However display still stays blank. To me it looks like either there is something wrong with the vbt sequence or those pins are misconfigured somehow.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> <li>You are on the CC list for the bug.</li> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>