On Sun, Jan 19, 2014 at 8:39 AM, Mauro Carvalho Chehab <m.chehab@xxxxxxxxxxx> wrote: > It seems that subsequent tuning makes the device worse, reducing the > maximum effective packet bandwidth. Btw, this happens with both xHCI > and EHCI drivers, so, it is not related to any USB 3.0 issue. I'm pretty sure I saw this and had a patch. I don't recall the exact circumstances under which it happened, but I believe it had to do with stopping and then restarting the streaming on the em28xx too quickly. The state machine inside the em28xx gets confused and you end up getting a misaligned stream (which is why you see hundreds of different PIDs in output from tools such as dvbtraffic). > Enabling some demux logs, it is possible to see that there are too many > FEC errors: > > [73514.186880] dvb_dmx_swfilter_packet: 4546 callbacks suppressed > [73514.186933] TEI detected. PID=0x17f data1=0xc1 > [73514.186965] TEI detected. PID=0x1c68 data1=0xbc > [73514.186993] TEI detected. PID=0x17f data1=0xc1 > [73514.187022] TEI detected. PID=0x1c68 data1=0xbc > [73514.187049] TEI detected. PID=0x17f data1=0xc1 > [73514.187080] TEI detected. PID=0x1c68 data1=0xbc > [73514.187105] TEI detected. PID=0x17f data1=0xc1 > [73514.194878] TEI detected. PID=0x1c68 data1=0xbc > [73514.194906] TEI detected. PID=0x17f data1=0xc1 > [73514.194927] TEI detected. PID=0x1c68 data1=0xbc > [73521.569205] TS speed 402 Kbits/sec Are these actually valid PIDs you're expecting data on? If not, then it could just be the issue I described above. Does the TEI check occur after it has found the SYNC byte? > I'm starting to suspect that this could be a hardware issue. > > It would be good to see if others can use it and tune to several > channels. > >> Ah, I didn't work at the remote controller yet. I'll handle it after >> doing more tests with the DVB functionality. > > Remote controller support was added. Should be trivial - I added the support for the em2874's RC using that device - the RC support went upstream years ago but not the actual board profile. Probably worth mentioning that while I got signal lock on ATSC, I didn't any significant analysis into the quality of the SNR. It's possible that additional optimization of the frontend is required in order to achieve optimal performance. Also, I didn't do the ClearQAM support yet, although that should be a fairly straightforward exercise (should just be another block in the set_frontend() call which sets the modulation appropriately). Devin -- Devin J. Heitmueller - Kernel Labs http://www.kernellabs.com -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
