From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans Verkuil Subject: Re: [PATCH] add raw video support for Samsung SUR40 touchscreen Date: Wed, 04 Feb 2015 11:22:02 +0100 Message-ID: <54D1F2CA.9020201@xs4all.nl> References: <1420626920-9357-1-git-send-email-floe@butterbrot.org> <64652239.MTTlcOgNK2@avalon> <54BE5204.3020600@xs4all.nl> <6025823.veVKIskIW2@avalon> <54BFA989.4090405@butterbrot.org> <54BFA9D6.1040201@xs4all.nl> <54CAA786.2040908@butterbrot.org> <54D13383.7010603@butterbrot.org> <54D1D37C.20701@xs4all.nl> <54D1EF91.8070805@butterbrot.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from lb3-smtp-cloud6.xs4all.net ([194.109.24.31]:49109 "EHLO lb3-smtp-cloud6.xs4all.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933347AbbBDKWW (ORCPT ); Wed, 4 Feb 2015 05:22:22 -0500 In-Reply-To: <54D1EF91.8070805@butterbrot.org> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Florian Echtler , Laurent Pinchart Cc: linux-input@vger.kernel.org, linux-media@vger.kernel.org On 02/04/15 11:08, Florian Echtler wrote: > Hello Hans, > > On 04.02.2015 09:08, Hans Verkuil wrote: >> I remain very skeptical about the use of dma-contig (or dma-sg for that >> matter). Have you tried using vmalloc and check if the USB core isn't >> automatically using DMA transfers for that? >> >> Basically I would like to see proof that vmalloc is not an option before >> allowing dma-contig (or dma-sg if you can figure out why that isn't >> working). >> >> You can also make a version with vmalloc and I'll merge that, and then >> you can look more into the DMA issues. That way the driver is merged, >> even if it is perhaps not yet optimal, and you can address that part later. > OK, that sounds sensible, I will try that route. When using > videobuf2-vmalloc, what do I pass back for alloc_ctxs in queue_setup? vmalloc doesn't need those, so you can just drop any alloc_ctx related code. Regards, Hans