<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO --- - [dual-gpu regression] Display shuts off when switching to discrete graphics card" href="https://bugs.freedesktop.org/show_bug.cgi?id=59785#c16">Comment # 16</a> on <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO --- - [dual-gpu regression] Display shuts off when switching to discrete graphics card" href="https://bugs.freedesktop.org/show_bug.cgi?id=59785">bug 59785</a> from <a class="email" href="mailto:daniel@ffwll.ch" title="Daniel Vetter <daniel@ffwll.ch>"> Daniel Vetter</a> <pre>Hm, that'll break pretty horribly, and I think we're looking at the wrong things. Can you play around whether just disabling the callbacks in intel_lvds.c for these function pointers (and not for all the other encoders helps)? I.e. something like: diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c index 8c61876..c1586d3 100644 --- a/drivers/gpu/drm/i915/intel_lvds.c +++ b/drivers/gpu/drm/i915/intel_lvds.c @@ -203,6 +203,8 @@ static void intel_disable_lvds(struct intel_encoder *encoder) struct drm_i915_private *dev_priv = dev->dev_private; u32 ctl_reg, stat_reg; + return; + if (HAS_PCH_SPLIT(dev)) { ctl_reg = PCH_PP_CONTROL; stat_reg = PCH_PP_STATUS; If that still works as a workaround, please test whether writing the ctl_reg or disabling the backlight is the crucial piece. I guess we just need to drill down until we have the root-cause like that, then either fix it or apply a quirk. But since you seem to be good at messsing with the source, that should be doable.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> <li>You are the assignee for the bug.</li> </ul> </body> </html>