From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-ee0-f46.google.com ([74.125.83.46]:65451 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752787Ab1LYNEW (ORCPT ); Sun, 25 Dec 2011 08:04:22 -0500 Received: by eekc4 with SMTP id c4so10551676eek.19 for ; Sun, 25 Dec 2011 05:04:20 -0800 (PST) Message-ID: <4EF72D61.9090001@gmail.com> Date: Sun, 25 Dec 2011 15:04:17 +0100 From: Dennis Sperlich MIME-Version: 1.0 To: Mauro Carvalho Chehab CC: linux-media@vger.kernel.org, Michael Krufky , Devin Heitmueller Subject: Re: em28xx_isoc_dvb_max_packetsize for EM2884 (Terratec Cinergy HTC Stick) References: <4EF64AF4.2040705@gmail.com> <4EF70077.5040907@redhat.com> In-Reply-To: <4EF70077.5040907@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: On 25.12.2011 11:52, Mauro Carvalho Chehab wrote: > On 24-12-2011 19:58, Dennis Sperlich wrote: >> Hi, >> >> I have a Terratec Cinergy HTC Stick an tried the new support for the DVB-C part. It works for SD material (at least for free receivable stations, I tried afair only QAM64), but did not for HD stations (QAM256). I have only access to unencrypted ARD HD, ZDF HD and arte HD (via KabelDeutschland). The HD material was just digital artefacts, as far as mplayer could decode it. When I did a dumpstream and looked at the resulting file size I got something about 1MB/s which seems a little too low, because SD was already about 870kB/s. After looking around I found a solution in increasing the isoc_dvb_max_packetsize from 752 to 940 (multiple of 188). Then an HD stream was about 1.4MB/s and looked good. I'm not sure, whether this is the correct fix, but it works for me. >> >> If you need more testing pleas tell. >> >> Regards, >> Dennis >> >> >> >> index 804a4ab..c518d13 100644 >> --- a/drivers/media/video/em28xx/em28xx-core.c >> +++ b/drivers/media/video/em28xx/em28xx-core.c >> @@ -1157,7 +1157,7 @@ int em28xx_isoc_dvb_max_packetsize(struct em28xx *dev) >> * FIXME: same as em2874. 564 was enough for 22 Mbit DVB-T >> * but not enough for 44 Mbit DVB-C. >> */ >> - packet_size = 752; >> + packet_size = 940; >> } >> >> return packet_size; > As you can see there at the code, the packet size depends on the chipset, as > not all will support 940 for packet size. > > Could you please provide us what was the chip detected id? > > It should be a message on your dmesg like: > > chip ID is em2870 > or > em28xx chip ID = 38 > > The patch should change it only for your specific chipset model, in order to > avoid regressions to other supported chipsets, like: > > int em28xx_isoc_dvb_max_packetsize(struct em28xx *dev) > { > unsigned int chip_cfg2; > unsigned int packet_size; > > switch (dev->chip_id) { > case CHIP_ID_EM2710: > case CHIP_ID_EM2750: > case CHIP_ID_EM2800: > case CHIP_ID_EM2820: > ... > case CHIP_ID_foo: > packet_size = 940; > ... > } > > return packet_size; > } > > The case you're touching seems to be for em2884, but the switch covers both > em2884 and em28174 (plus the default for newer chipsets). dmesg says: em28xx #0: chip ID is em2884 so a patch would be more like: index 804a4ab..9280251 100644 --- a/drivers/media/video/em28xx/em28xx-core.c +++ b/drivers/media/video/em28xx/em28xx-core.c @@ -1151,6 +1151,8 @@ int em28xx_isoc_dvb_max_packetsize(struct em28xx *dev) packet_size = 564; break; case CHIP_ID_EM2884: + packet_size = 940; + break; case CHIP_ID_EM28174: default: /* > Maybe Michael/Devin may have something to say, with regards to a way to detect > the maximum supported packet size by each specific em28xx model. This would be fine, I tried also 1128 (6 times 188), but then mplayer did not play any more. I then tried 1034, but then I got the message " submit of urb 0 failed (error=-90)", so I guess there have to be integer multiples of 188. Regards, Dennis