From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from oyp.chewa.net ([91.121.6.101]:60654 "EHLO oyp.chewa.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752790Ab3CCJht convert rfc822-to-8bit (ORCPT ); Sun, 3 Mar 2013 04:37:49 -0500 Received: from leon.localnet (cs181242165.pp.htv.fi [82.181.242.165]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: remi) by oyp.chewa.net (Postfix) with ESMTPSA id E6FB620145 for ; Sun, 3 Mar 2013 10:37:45 +0100 (CET) From: "=?utf-8?q?R=C3=A9mi?= Denis-Courmont" To: linux-media@vger.kernel.org Subject: uvcvideo USERPTR mode busted? Date: Sun, 3 Mar 2013 11:37:44 +0200 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8BIT Message-Id: <201303031137.44917@leon.remlab.net> Sender: linux-media-owner@vger.kernel.org List-ID: Hello, Trying to use USERPTR buffers with UVC, user space gets stuck either in poll(POLLIN) or in ioctl(VIDIOC_DQBUF). It seems the UVC driver never ever returns a frame in USERPTR mode. The symptoms are identical with kernel versions 3.6, 3.7 and 3.8. I also tested 3.2, but it did not support USERPTR. Tested hardware was Logitech HD Pro Webcam C920 with YUY2 pixel format. The same hardware and the same driver work fine with MMAP buffers. The same USERPTR userspace code works fine with the vivi test device... Did any have any better luck? -- Rémi Denis-Courmont http://www.remlab.net/