<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#c13">Comment # 13</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:jenny.tc@intel.com" title="Jenny TC <jenny.tc@intel.com>"> Jenny TC</a> <pre>I faced the same issue and my panel doesnt support AUX Backlight Enable cat /sys/kernel/debug/dri/0/eDP-1/i915_dpcd 0000: 12 0a 84 41 00 00 01 c0 02 03 00 00 00 0b 00 0070: 01 00 0080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0100: 0a 84 00 00 00 00 00 00 01 00 00 0200: 01 00 77 77 01 01 00 00 0600: 01 0700: 02 0701: bb ff 00 00 0720: 00 00 00 00 06 06 10 00 01 00 00 00 01 80 00 00 0732: 00 14 With below change its working for my panel, but this wont work for the issue reported in this bug since the panel seems to have wrong DPCD capabilities. intel_dp_aux_display_control_heuristic(struct intel_connector *connector) struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base); uint8_t reg_val; + /* Panel dosn't support enabling AUX Backlight control */ + if (!(intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_AUX_ENABLE_CAP)) { + return false; + } /* Panel doesn't support adjusting backlight brightness via PWN pin */ if (!(intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_PWM_PIN_CAP)) return true;</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>