From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-pf0-f196.google.com ([209.85.192.196]:33676 "EHLO mail-pf0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933536AbcIWAXf (ORCPT ); Thu, 22 Sep 2016 20:23:35 -0400 Subject: Re: g_webcam Isoch high bandwidth transfer To: Bin Liu , Felipe Balbi , linux-usb@vger.kernel.org, linux-media@vger.kernel.org References: <20160920170441.GA10705@uda0271908> <871t0d4r72.fsf@linux.intel.com> <20160921132702.GA18578@uda0271908> <87oa3go065.fsf@linux.intel.com> <87lgyknyp7.fsf@linux.intel.com> <87d1jw6yfd.fsf@linux.intel.com> <20160922133327.GA31827@uda0271908> <87a8ezn2av.fsf@linux.intel.com> <20160922201131.GD31827@uda0271908> From: yfw Message-ID: <05d5b2dd-0c1b-e7bd-afc5-313b5a5ab268@gmail.com> Date: Fri, 23 Sep 2016 08:23:25 +0800 MIME-Version: 1.0 In-Reply-To: <20160922201131.GD31827@uda0271908> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Hi Bin, On 2016/9/23 4:11, Bin Liu wrote: > +Fengwei Yin per his request. Thanks a lot for adding me to this thread. > > On Thu, Sep 22, 2016 at 10:48:40PM +0300, Felipe Balbi wrote: >> >> Hi, >> >> Bin Liu writes: >> >> [...] >> >>>> Here's one that actually compiles, sorry about that. >>> >>> No worries, I was sleeping ;-) >>> >>> I will test it out early next week. Thanks. >> >> meanwhile, how about some instructions on how to test this out myself? >> How are you using g_webcam and what are you running on host side? Got a >> nice list of commands there I can use? I think I can get to bottom of >> this much quicker if I can reproduce it locally ;-) I am using similar use case with a different gadget function driver. > > On device side: > - first patch g_webcam as in my first email in this thread to enable > 640x480@30fps; > - # modprobe g_webcam streaming_maxpacket=3072 > - then run uvc-gadget to feed the YUV frames; > http://git.ideasonboard.org/uvc-gadget.git - I am using uvc function driver + configfs. - maxpacket in configfs was set to 3072. - uvc-gadget from the same source as Bin. > > On host side: > - first check the device ep descriptor, which should be > wMaxPacketSize 0x1400 3x 1024 bytes > - then use luvcview or yavta to capture the video stream - lsusb give me same wMaxPacketSize. - I am using example (changed a little bit) from libuvc. Regards Yin, Fengwei > > Capture the bus trace to check if multiple IN transactions happens in > each SOF. > > The data buffer size in the usb_request coming from the uvc driver is > 5120 bytes, so there should be 3 IN transactions if the UDC works > correctly. > > Regards, > -Bin. >