<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - [SKL] DPCD backlight causes black screen on ThinkPad X1 Carbon 4th Gen" href="https://bugs.freedesktop.org/show_bug.cgi?id=101619#c11">Comment # 11</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - [SKL] DPCD backlight causes black screen on ThinkPad X1 Carbon 4th Gen" href="https://bugs.freedesktop.org/show_bug.cgi?id=101619">bug 101619</a> from <a class="email" href="mailto:david.weinehall@intel.com" title="David Weinehall <david.weinehall@intel.com>"> David Weinehall</a> <pre>It seems that the issue is with DBC rather than DPCD backlight as I first thought; reverting the DBC patch (or disabling dbc) seems to be enough to get things working. Setting min=100, max=100 didn't solve anything, neither did min=40, max=60 (just in case the display has some weird hangup about 100%). The patch that introduces the issue is: ae25eceab616d16a07bcaa434b84463d58a3bdc3 On a somewhat tangential note, having DBC enabled by default feels very dubious, in my opinion, especially since it's not a user adjustable option. If there's no way to toggle DBC on/off from userspace I much rather adjust the brightness using Fn + F5/F6 than have the system decide what's best for me. This of course only applies if it's a strict choice between DBC & manual control; if the DBC only adjust the brightness already set by the user, then it's a different story, obviously.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are on the CC list for the bug.</li> <li>You are the assignee for the bug.</li> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>