From: Daniel Vetter Date: Mon, 17 Sep 2012 20:27:21 +0000 (+0200) Subject: drm/i915: fix OOPS in lid_notify X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=3b7a89fce3e3dc96b549d6d829387b4439044d0d;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git drm/i915: fix OOPS in lid_notify This goes back to commit c1c7af60892070e4b82ad63bbfb95ae745056de0 Author: Jesse Barnes Date: Thu Sep 10 15:28:03 2009 -0700 drm/i915: force mode set at lid open time It was used to fix an issue on a i915GM based Thinkpad X41, which somehow clobbered the modeset state at lid close time. Since then massive amounts of things changed: Tons of fixes to the modeset sequence, OpRegion support, better integration with the acpi code. Especially OpRegion /should/ allow us to control the display hw cooperatively with the firmware, without the firmware clobbering the hw state behind our backs. So it's dubious whether we still need this. The second issue is that it's unclear who's responsibility it actually is to restore the mode - Chris Wilson suggests to just emit a hotplug event and let userspace figure things out. The real reason I've stumbled over this is that the new modeset code breaks drm_helper_resume_force_mode - it OOPSes derefing a NULL vfunc pointer. The reason this wasn't caught in testing earlier is that in commit c9354c85c1c7bac788ce57d3c17f2016c1c45b1d Author: Linus Torvalds Date: Mon Nov 2 09:29:55 2009 -0800 i915: fix intel graphics suspend breakage due to resume/lid event confusion logic was added to _not_ restore the modeset state after a resume. And since most machines are configured to auto-suspend on lid-close, this neatly papered over the issue. Summarizing, this shouldn't be required on any platform supporting OpRegion. And none of the really old machines I have here seem to require it either. Hence I'm inclined to just rip it out. But in case that there are really firmwares out there that clobber the hw state, replace it with a call to intel_modset_check_state. This will ensure that we catch any issues as soon as they happen. Cc: Chris Wilson Acked-by: Jesse Barnes Signed-off-by: Daniel Vetter --- diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c index 564689554989..dc9f9ff34d8c 100644 --- a/drivers/gpu/drm/i915/intel_lvds.c +++ b/drivers/gpu/drm/i915/intel_lvds.c @@ -527,7 +527,7 @@ static int intel_lid_notify(struct notifier_block *nb, unsigned long val, dev_priv->modeset_on_lid = 0; mutex_lock(&dev->mode_config.mutex); - drm_helper_resume_force_mode(dev); + intel_modeset_check_state(dev); mutex_unlock(&dev->mode_config.mutex); return NOTIFY_OK;