From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Pinchart Subject: Re: [PATCH] add raw video support for Samsung SUR40 touchscreen Date: Wed, 04 Feb 2015 13:34:06 +0200 Message-ID: <10701805.dDfTQCs2MO@avalon> References: <1420626920-9357-1-git-send-email-floe@butterbrot.org> <54D1F2CA.9020201@xs4all.nl> <54D1FAFA.3070506@butterbrot.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <54D1FAFA.3070506@butterbrot.org> Sender: linux-media-owner@vger.kernel.org To: Florian Echtler Cc: Hans Verkuil , linux-input@vger.kernel.org, linux-media@vger.kernel.org List-Id: linux-input@vger.kernel.org Hi Florian, On Wednesday 04 February 2015 11:56:58 Florian Echtler wrote: > On 04.02.2015 11:22, Hans Verkuil wrote: > > On 02/04/15 11:08, Florian Echtler wrote: > >> On 04.02.2015 09:08, Hans Verkuil wrote: > >>> 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. > > That's what I assumed, however, I'm running into the same problem as > with dma-sg when I switch to vmalloc...? I don't expect vmalloc to work, as you can't DMA to vmalloc memory directly without any IOMMU in the general case (the allocated memory being physically fragmented). dma-sg should work though, but you won't be able to use usb_bulk_msg(). You need to create the URBs manually, set their sg and num_sgs fields and submit them. > I've sent a "proper" patch submission again, which has all the other > issues from the previous submission fixed. I'm hoping you can maybe have > a closer look and see if I'm doing anything subtly wrong which causes > both vmalloc and dma-sg to fail while dma-contig works. -- Regards, Laurent Pinchart