From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]:35902 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750993Ab1HIT4W (ORCPT ); Tue, 9 Aug 2011 15:56:22 -0400 Message-ID: <4E41912F.50901@redhat.com> Date: Tue, 09 Aug 2011 21:57:35 +0200 From: Hans de Goede MIME-Version: 1.0 To: Alan Stern CC: Sarah Sharp , Greg KH , Mauro Carvalho Chehab , linux-usb@vger.kernel.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, libusb-devel@lists.sourceforge.net, Alexander Graf , Gerd Hoffmann , hector@marcansoft.com, Jan Kiszka , Stefan Hajnoczi , pbonzini@redhat.com, Anthony Liguori , Jes Sorensen , Oliver Neukum , Felipe Balbi , Clemens Ladisch , Jaroslav Kysela , Takashi Iwai , Laurent Pinchart , Theodore Kilgore , Adam Baker Subject: Re: USB mini-summit at LinuxCon Vancouver References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Hi, On 08/09/2011 04:19 PM, Alan Stern wrote: > On Tue, 9 Aug 2011, Hans de Goede wrote: > >> I would really like to see the dual mode camera and TV tuner discussion >> separated. They are 2 different issues AFAIK. >> >> 1) Dual mode cameras: >> >> In the case of the dual mode camera we have 1 single device (both at >> the hardware level and at the logical block level), which can do 2 things, >> but not at the same time. It can stream live video data from a sensor, >> or it can retrieve earlier taken pictures from some picture memory. >> >> Unfortunately even though these 2 functions live in a single logical block, >> historically we've developed 2 drivers for them. This leads to fighting >> over device ownership (surprise surprise), and to me the solution is >> very clear, 1 logical block == 1 driver. > > According to Theodore, we have developed 5 drivers for them because the > stillcam modes in different devices use four different vendor-specific > drivers. Yes, but so the the webcam modes of the different devices, so for the 5 (not sure if that is the right number) dual-cam mode chipsets we support there will be 5 drivers, each supporting both the webcam and the access to pictures stored in memory of the chipset they support. So 5 chipsets -> 5 drivers each supporting 1 chipset, and both functions of the single logical device that chipset represents. > Does it really make sense to combine 5 drivers into one? Right, that is not the plan. The plan is to simply stop having 2 drivers for 1 logical (and physical) block. So we go from 10 drivers, 5 stillcam + 5 webcam, to just 5 drivers. We will also likely be able to share code between the code for the 2 functionalities for things like generic set / get register functions, initialization, etc. Regards, Hans