From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Wilson Subject: Re: [PATCH] drm/fb-helper: delay hotplug handling when partially bound Date: Fri, 15 Jun 2012 10:32:20 +0100 Message-ID: <1339752751_24743@CP5-2952> References: <1339750882-23398-1-git-send-email-daniel.vetter@ffwll.ch> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from fireflyinternet.com (smtp.fireflyinternet.com [109.228.6.236]) by gabe.freedesktop.org (Postfix) with ESMTP id 8A2689E94F for ; Fri, 15 Jun 2012 02:32:37 -0700 (PDT) In-Reply-To: <1339750882-23398-1-git-send-email-daniel.vetter@ffwll.ch> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org Errors-To: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org To: Dave Airlie Cc: Daniel Vetter , DRI Development List-Id: dri-devel@lists.freedesktop.org On Fri, 15 Jun 2012 11:01:22 +0200, Daniel Vetter wrote: > Ok, this requires quite a dance to actually hit: > 1) We plug in a 2nd screen, enable it in both X and (by vt-switching) > in the fbcon. > 2) We disable that screen again in with xrandr. > 3) We vt-switch again, so that fbcon displays on the 2nd screen, but X > on the first screen. This obviously needs a driver that doesn't switch > off unused functions when regaining the VT. > 3) When X controls the vt, we unplug that screen. > > Now drm_fb_helper_hotplug_event we noticed that that some crtcs are > bound, but because we still have the fbcon on the 2nd screeen we also > have bound set. Which means the fbcon wrongly assumes it's in control > of everything an happily disables the output on the 2nd screen, but > enables its fb on the first screen. > > Work around this issue by counting how many crtcs are bound and how > many are bound to fbcon and assuming that when fbcon isn't bound to > all of them, it better not touch the output configuration. > > Conceptually this is the same as only restoring the fbcon output > configuration on the driver's ->lastclose, when we're sure that no one > else is using kms. So this should be consistent with existing kms > drivers. > > Chris has created a separate patch for the intel ddx, but I think we > should fix this issue here regardless - the fbcon messing with the > output config while it's not fully in control simply isn't a too > polite behaviour. > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=50772 > Tested-by: Maxim A. Nikulin > Signed-Off-by: Daniel Vetter Reviewed-by: Chris Wilson -Chris -- Chris Wilson, Intel Open Source Technology Centre