From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomi Valkeinen Subject: RE: [RFC][PATCH] omapfb: Condition mutex acquisition Date: Tue, 29 Sep 2009 17:53:24 +0300 Message-ID: <1254236004.23991.17.camel@tubuntu> References: ,<1254234160.23991.1.camel@tubuntu> Reply-To: tomi.valkeinen@nokia.com Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from smtp.nokia.com ([192.100.122.233]:40109 "EHLO mgw-mx06.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752287AbZI2Oxc (ORCPT ); Tue, 29 Sep 2009 10:53:32 -0400 In-Reply-To: Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: "ext Aguirre Rodriguez, Sergio Alberto" Cc: "Deak Imre (Nokia-D/Helsinki)" , "linux-omap@vger.kernel.org" On Tue, 2009-09-29 at 16:34 +0200, ext Aguirre Rodriguez, Sergio Alberto wrote: > From: Tomi Valkeinen [tomi.valkeinen@nokia.com] > Sent: Tuesday, September 29, 2009 9:22 AM > > On Tue, 2009-09-29 at 16:14 +0200, ext Aguirre Rodriguez, Sergio Alberto > > wrote: > > > From: Sergio Aguirre > > > > > > Acquiring mutex before framebuffer registration doesn't make sense, > > > As there's no danger of external access to the memory related fields. > > > > What problem does this patch solve? It makes the code more complex. > > > > Tomi, > > Thanks for your time. > > The problem was that, during platform driver registration, > this sequence was executed: > > -> omapfb_probe > -> omapfb_do_probe > -> planes_init > -> fbinfo_init > -> set_fb_fix > ... > -> register_framebuffer > > And then, inside that function, an attempt of acquiring a > mutex failed, because it wasn't initialized before trying it: > > mutex_lock(&fbi->mm_lock); > > It is actually initialized later in omapfb_do_probe in register_framebuffer call. > > So, how is the best to solve this then? Oh, I wasn't implying that there's something wrong with the fix, I just didn't know what it was fixing =). Looks like a valid fix to me. Tomi