-----Original Message----- From: Andy Walls [mailto:awalls@xxxxxxxxx] Sent: Wednesday, December 17, 2008 3:51 AM To: Daniel Perzynski Cc: 'Devin Heitmueller'; linux-dvb@xxxxxxxxxxx Subject: RE: Avermedia A312 - patch for review On Tue, 2008-12-16 at 12:29 +0100, Daniel Perzynski wrote: > From: Devin Heitmueller [mailto:devin.heitmueller@xxxxxxxxx] > On Mon, Dec 15, 2008 at 8:04 PM, Andy Walls <awalls@xxxxxxxxx> wrote: > > On Mon, 2008-12-15 at 18:27 -0500, Devin Heitmueller wrote: > >> On Mon, Dec 15, 2008 at 6:23 PM, Daniel Perzynski > >> <Daniel.Perzynski@xxxxxxxx> wrote: > > > >> > Could you please look at the wiki for that card and tell me what will > be the > >> > analog video decoder for that card (I don't have /dev/videoX device). > >> > >> Hmm.... It's a cx25843. I would have to look at the code to see how > >> to hook that into the CY7C68013A bridge. I'll take a look tonight > >> when I get home. > > > > The cxusb.[ch] files seem to devoid of analog support. There's this > > comment which sums it up: > > > > * TODO: Use the cx25840-driver for the analogue part > > > > > > Although the linux/media/video/pvrusb2 driver appears to have at least > > two hybrid boards with a cx2584x and an FX2 (WinTV HVR-1900 and HVR-1950 > > in pvrusb2_devattr.c). Maybe that driver could help... (or maybe I > > haven't got a clue :] ) > > > > Regards, > > Andy > > Daniel - This is going to be a project - we're not talking adding just > > another device profile. Analog support is a huge piece of the > > framework that this driver outright doesn't exist. Someone would have > > to add analog support to dvb_usb and then make it work with the cxusb > > driver, and then add the appropriate device profile for the Avermedia > > A312. > Hmm, not good then :( How we can start that project? I have to tell you that > I'm not a programmer and I've added a312 support to cxusb based on the > similarities to Avermedia Volar. Andy Walls' off the cuff steps to starting a project: 1. Define the requirements: analog TV and video, FM radio, and ideally digital TV support for the AverMedia A312 in v4l-dvb. Done. 2. Identify resources and constraints: limited hardware test asset availability due to laptop family specific packaging, limits of time for experienced programmers, number of testers, ability of testers to exercise all functions (e.g. ATSC in Europe is unlikely), who's going to do the coding and the testing?, etc. 3. Develop some strategic options: add analog support to cxusb, modify pvrusb2, write a new driver based on existing one, etc. 4. Asses relative feasibility of strategies and scope the work 5. Develop a work break down of the preferred strategy, with tasks and milestones to accomplish, and set an overall schedule goal. Of the above, I'd suggest assessing a strategy of modifying the pvrusb2 driver first, as I have a feeling that will have the best return on time invested. Mike Isley would probably be able to provide you with an expert opinion on feasibility of modifying pvrusb2 to support the A312, given that he maintains the pvrusb2 driver, IIRC, and you can point him to fairly decent information on the wiki page for the A312. > There is a radio also in that card (I don't know which chipset is > responsible for that) + WM8739 for which the driver do exist (wm8739.c). Likely the tuner outputs baseband FM L and R audio that's fed into the WM8739 for digitization, and then passed to the CX25843 as serial audio data on the I2S input to the CX25843. That's the way it works on many of the ivtv and cx18 supported cards. > I > can try to modify pvrusb2 but the question is if we shouldn't have one > "driver" to support both analog and digital TV + Radio on that card? That's an easy one to answer: Why shouldn't one driver do it? There's precedent as other drivers do this: At least the cx18 driver supports cards that can capture analog video, FM radio and digital TV. The ivtv driver supports cards that perform analog video capture and FM radio capture. The real answer is that there are finite resources available (people with time and experience and test assets) and that will limit what gets done. So what's most important to you to get working? (Not that I have time to really help - just apparently time enough to write long rambling e-mails) Regards, Andy > Daniel, Hi Andy, Thank you very much for that long and valuable post. The top priority for me would be analog TV + Radio. If one driver can do analog TV and Video + Radio and another digital TV the option would be to update pvrusb2 driver with support for that card (analog TV + radio) and test my patch to cxusb driver for digital TV (I need to find someone with A312 card in his/her laptop). Regards, _______________________________________________ linux-dvb mailing list linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
