From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.kapsi.fi ([217.30.184.167]:57010 "EHLO mail.kapsi.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751854AbaBGVLM (ORCPT ); Fri, 7 Feb 2014 16:11:12 -0500 Message-ID: <52F54BEE.3080603@iki.fi> Date: Fri, 07 Feb 2014 23:11:10 +0200 From: Antti Palosaari MIME-Version: 1.0 To: Manu Abraham , David Jedelsky CC: Linux Media Mailing List Subject: Re: [PATCH] [media] stb0899: Fix DVB-S2 support for TechniSat SkyStar 2 HD CI USB ID 14f7:0002 References: <1391679907-17876-1-git-send-email-david.jedelsky@gmail.com> 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: On 07.02.2014 22:54, Manu Abraham wrote: > On Sat, Feb 8, 2014 at 1:19 AM, David Jedelsky wrote: >>> That changes I2C functionality from STOP + START to repeated START. >>> Current functionality looks also very weird, as there is 5 messages sent, >>> all with STOP condition. I am not surprised if actually bug is still in >>> adapter... Somehow it should be first resolved how those messages are send, >>> with repeated START or STOP. And fix I2C client or adapter or both. >>> >>> regards >>> Antti >> >> >> >> Manu, Antti, >> >> Thank you for your response. I agree that the code is somewhat peculiar and >> it could be worthy to review it using documentation before I leave it as bug >> in my hw. Unfortunately I don't own appropriate documentation. If you can >> supply it I can look at it. > > I can assure you that the STB0899 driver works well for S2 with most > USB bridges and PCI bridges, which brings me to the fact that the issue > does not exist with the STB0899 driver. > > Regarding the documentation, I don't have any wrt to the USB bridge, but > only for the demodulator, tuner. But my hands are tied on that front, due to > NDA's and agreements. > > Looking further in my hardware museum, I did find a > Technisat Skystar USB2 HD CI REV 2.0 > > The information on a white sticker on the PCB states: > Model AD-SB301, Project ID: 6027 > DVB-S2, CI, USB Box (on-line update) > H/W Ver: A1, PID/VID: 14F7 / 0002 > > manufactured and sent to me by Azurewave. > > It has a broken ferrite cored inductor on it, which appears to be on the > power line to the demodulator/tuner. > > The PID/VID looks exactly the same as yours. If you have a firmware bug, > maybe it helps to update the firmware online ? (I guess the windows driver > uses some stock Cypress driver, from what I can imagine ?) > > I had similar problems as you state, when I worked with a prototype version > of the Mantis PCI chipset where it had some issues regarding repeated > starts. I can't really remember the exact issue back then, but I do remember > the issue being tuner related as well, since the write to the tuner would reach > the very first tuner register alone. The communications to the tuner are > through a repeater on the demodulator. > > This issue was addressed with an ECO Metal fix for the PCI bridge, but that > did eventually result in a newer chip though. > > The problem could likely be similar with your USB bridge. Maybe it is a > driver bug too .. I haven't looked deeply at the az6027 driver. It is almost 100% sure I2C adapter or client bug. az6027 driver i2c adapter seems to have some weird looking things, it behaves differently according I2C slave address used. If I didn't read code wrong, in that case it does to branch "if (msg[i].addr == 0xd0)". And looking that logic reveals it supports only 2 I2C transfers: for reg read: START + write + REPEATED START + read + STOP for reg write: START + write + STOP So that read operation (START + read + STOP) used by STB0899 is not implemented at all. regards Antti -- http://palosaari.fi/