On Sun, Jul 8, 2012 at 2:28 PM, Andy Walls <[email protected]> wrote: > On Sat, 2012-07-07 at 12:44 -0500, Robert Rust wrote: >> After weeks of headaches trying to get my HVR-1600 to work, I finally >> determined with help from this list that the H77 chipset on my >> motherboard was the root of my problems, so I replaced the board. I >> am now trying to set up my MythTV backend in a Xen domU after >> verifying that it can capture outside of Xen and in the Xen dom0 host. > > What is the difference between Xen domain dom0 and domU (for a Xen newb > like me)? > > >> I can tune to channels and I get data when I cat /dev/video0 ... but >> the data doesn't seem to be valid video. > > You may wan to try using v4l2-ctl to enumerate the controls (with menu > options) and then changes the card to generate an MPEG2 TS instead of > the default MPEG2 PS. A TS is more robust to small amounts of data loss > than a PS, so maybe things will be a little better. > > >> Does anybody have input on how I can work towards a resolution on >> this? > > Note the CX23418 is very latency sensitive. If the guest responds too > slowly to CX23418 interrupts, it will miss the CX23418 mailbox payload > data and hence lose video buffer data. The CX23418 won't wait forever > for the OS driver and will move on. (This is a firmware bug IMO, but > likely considered a required feature if you ask Conexant). > > Regards, > Andy >
Andy, I did manage to get it to work. After trying my PVR-250 and getting DMA timemouts, I noticed I missed passing a kernel parameter required for PCI Passthrough (iommu=soft). After fixing that and putting the HVR-1600 back in, I encountered the known issue with missing audio, which resolved itself after the first capture (the MythTV wiki has a note on that as well). In regards to dom0 vs. domU ... I think the best way of explaining it (assuming I understand it correctly ... I'm rather new to Xen myself) is that the dom0 is the "host" (sits 1 layer above the actual Xen kernel) and so has direct access to hardware out-of-the-box and the domU is a virtual host which requires tricks and hardware/software support to pass it bare hardware. Thanks for the assistance! -Robert _______________________________________________ ivtv-users mailing list [email protected] http://ivtvdriver.org/mailman/listinfo/ivtv-users
