From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesse Barnes Subject: Re: [PATCH 3/6] drm/i915: Wrap the preallocated BIOS framebuffer and preserve for KMS fbcon v7 Date: Fri, 13 Dec 2013 16:43:50 -0800 Message-ID: <20131213164350.49c244c8@jbarnes-desktop> References: <1386880917-2951-1-git-send-email-jbarnes@virtuousgeek.org> <1386880917-2951-3-git-send-email-jbarnes@virtuousgeek.org> <20131212225437.GT9804@phenom.ffwll.local> <20131213110905.06046c4e@jbarnes-desktop> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from alt-proxy13.mail.unifiedlayer.com (alt-proxy13.mail.unifiedlayer.com [67.222.34.81]) by gabe.freedesktop.org (Postfix) with SMTP id D8876FB4F6 for ; Fri, 13 Dec 2013 16:42:06 -0800 (PST) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces@lists.freedesktop.org Errors-To: intel-gfx-bounces@lists.freedesktop.org To: Daniel Vetter Cc: intel-gfx List-Id: intel-gfx@lists.freedesktop.org On Fri, 13 Dec 2013 21:47:45 +0100 Daniel Vetter wrote: > On Fri, Dec 13, 2013 at 8:09 PM, Jesse Barnes wrote: > > On Thu, 12 Dec 2013 23:54:37 +0100 > > Daniel Vetter wrote: > > > >> > @@ -258,8 +357,102 @@ static void intel_fbdev_destroy(struct drm_device *dev, > >> > > >> > drm_fb_helper_fini(&ifbdev->helper); > >> > > >> > - drm_framebuffer_unregister_private(&ifbdev->ifb.base); > >> > - intel_framebuffer_fini(&ifbdev->ifb); > >> > + drm_framebuffer_unregister_private(&ifbdev->fb->base); > >> > + intel_framebuffer_fini(ifbdev->fb); > >> > + kfree(ifbdev->fb); > >> > >> No need to go the private fb route here anymore since now the fb is > >> free-standing. Normal refcounting should work. But a separate prep/cleanup > >> patch (prep since switching ifbdev->fb from struct to point would look > >> neat as a separate patch). > > > > Oh and can you explain this? I wouldn't be surprised if I got the > > refcounting wrong, but given how tricky it can be, can you explain > > where we'll take the ref here, and show that the right thing will > > happen if/when we mode set away from this buffer? > > > > I haven't actually seen a bug here with or without this patch (no > > crashes or warns), but I thought I needed this to make sure the obj > > didn't get a negative count after a mode set... > > There's no bug here, and if you underrun the the refcount the current > logic here won't help. It's just that the explicit call to _fini was > an artifact of the old logic with embedding the framebuffer into the > fbdev structure. But now that the fbdev framebuffer is freestanding > there's no need for that - you exactly duplicate > intel_user_framebuffer_destroy now. > > So a simple drm_framebuffer_unreference will do the trick and makes it > clearer that this is now just another fb object with normal lifetime > rules. > > I guess I score points for unclear review here ;-) Oh! I had this mixed up with the refs I take in the init_bios code... I thought you were saying those weren't necessary and I was getting really confused. This is just fixing up existing code to use the new field name, so no functional change. I see what you mean about splitting out the field change, but now that would be a pain :/ Do you want the above removed as a separate patch regardless of where the rest of the patches go? Thanks, -- Jesse Barnes, Intel Open Source Technology Center