From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-wy0-f174.google.com ([74.125.82.174]:45672 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752839Ab1ARU6c (ORCPT ); Tue, 18 Jan 2011 15:58:32 -0500 Received: by wyb28 with SMTP id 28so68808wyb.19 for ; Tue, 18 Jan 2011 12:58:31 -0800 (PST) Subject: Re: [PATCH][_COMPAT_H] git://linuxtv.org/media_build.git Legacy issues From: Malcolm Priestley To: Andy Walls Cc: linux-media@vger.kernel.org, ivtv-devel@ivtvdriver.org In-Reply-To: <1295317361.12544.22.camel@localhost> References: <1295305161.2162.21.camel@tvboxspy> <1295317361.12544.22.camel@localhost> Content-Type: text/plain; charset="UTF-8" Date: Tue, 18 Jan 2011 20:49:32 +0000 Message-ID: <1295383772.2215.1.camel@tvboxspy> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit List-ID: Sender: On Mon, 2011-01-17 at 21:22 -0500, Andy Walls wrote: > On Mon, 2011-01-17 at 22:59 +0000, Malcolm Priestley wrote: > > Clean up legacy issues for error free build on Kernel 2.6.37. > > > > Today while testing on Kernel 2.6.35 latest tarball throws error with > > alloc_ordered_workqueue undefined on Kernels less than 2.6.37. defined back to > > create_singlethread_workqueue. > > > > Please test on other kernel versions. > > > > Tested-on 2.6.35/37 by: Malcolm Priestley > > > > > > +#define alloc_ordered_workqueue(a,b) create_singlethread_workqueue(a) > > That will get cx18 to compile. However, I can tell you without testing, > the latest cx18 driver could badly affect system event processing > performance on older kernels. > > This is because another change happened at the same time as the change > to call alloc_ordered_workqueue(). A kernel version before that, CMWQ > was added to the kernel, so there was no longer a need for the > cx18_out_work workqueue. So now the cx18_out_work workqueue has been > removed from the cx18 driver. > > In the older kernels without CMWQ and without the cx18_out_work > workqueue, outgoing cx18 buffer work will get queued to the [keventd/M] > kernel threads. Unrelated system work being processed by [keventd/M] > threads will regularly find itself *waiting for the CX23418 hardware* to > respond to firmware commands. > > It would be better to not allow the newest cx18 driver version to > compile on older kernels. Yes, after review, it would be wise to disable the cx18 driver. However, there are more problems with the media_build today on all kernels. For now the patch is withdrawn. Regards malcolm