From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.linuxfoundation.org ([140.211.169.12]:44926 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752366AbdBNTlr (ORCPT ); Tue, 14 Feb 2017 14:41:47 -0500 Date: Tue, 14 Feb 2017 11:41:46 -0800 From: Greg KH To: Mauro Carvalho Chehab Cc: Linux Media Mailing List , Mauro Carvalho Chehab , Mauro Carvalho Chehab , stable@vger.kernel.org, #@smtp.w2.samsung.com, For@smtp.w2.samsung.com, 4.9+@smtp.w2.samsung.com Subject: Re: [PATCH] siano: make it work again with CONFIG_VMAP_STACK Message-ID: <20170214194146.GA28566@kroah.com> References: <08f1b470a156163cc3394f73bcbaea3925b6f376.1487100723.git.mchehab@s-opensource.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <08f1b470a156163cc3394f73bcbaea3925b6f376.1487100723.git.mchehab@s-opensource.com> Sender: linux-media-owner@vger.kernel.org List-ID: On Tue, Feb 14, 2017 at 05:32:11PM -0200, Mauro Carvalho Chehab wrote: > Reported as a Kaffeine bug: > https://bugs.kde.org/show_bug.cgi?id=375811 > > The USB control messages require DMA to work. We cannot pass > a stack-allocated buffer, as it is not warranted that the > stack would be into a DMA enabled area. > > On Kernel 4.9, the default is to not accept DMA on stack anymore. > > Tested with USB ID 2040:5510: Hauppauge Windham > > Cc: stable@vger.kernel.org # For 4.9+ Unless there is some major reason, this should go into _all_ stable releases, as the driver would be broken on them all for platforms that can't handle USB data that is not DMA-able. This has been a requirement for USB drivers since the 2.2 days. thanks, greg k-h