On Sun, Jul 30, 2017 at 8:55 AM, Dave Newman <d.r.newman@xxxxxxxxxxxxxxxxxx> wrote: > I can confirm the problems with the cx23885 driver reported by Steven > Toth on 6 June 2017. He found that: > >> I tried the card in a different older Intel i7 board and it worked >> flawlessly. I then started to wonder if it was some new >> incompatibility introduced with Kaby Lake. I had tweaked the UEFI >> settings on the new Kaby Lake board to enable VT-d/VT-x since I wanted >> to run Linux as a host OS with Windows 10 running on top of qemu/KVM. >> Upon resetting the UEFI settings to their defaults (VT-d/VT-x >> disabled) the card worked without issue. > > Like him: > > - I have a recent Hauppauge WinTV-quadHD TV tuner PCIe card > > - I have a new fast multi-processor CPU. He found that there were no > problems on > > - Enabling debug output for the cx23885 driver *fixes* the issue > (options cx23885 debug=5), letting me run a scan of DVB channels. > > Unlike him: > > - my CPU is an 8 core Ryzen 1700 on a new Gigabyte AB350 motherboard. > > - turning off iommu does not fix the problem. > > I do not know the cx23885 code well enough to propose any patches, but I > am happy to do debugging and testing. One thing I noticed is that > i2cdetect output differs from that on > https://www.linuxtv.org/wiki/index.php/Hauppauge_WinTV-quadHD_(DVB-T/T2/C). > E.g. > > 0 1 2 3 4 5 6 7 8 9 a b c d e f > 00: -- -- -- -- -- -- -- -- -- -- -- -- -- > 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- > 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- > 30: 30 31 32 33 34 35 36 37 -- -- -- -- -- -- -- -- > 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- > 50: 50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f > 60: -- -- -- -- UU -- UU -- -- -- -- -- -- -- -- -- > 70: -- -- -- -- -- -- -- -- > > Anything from 60 and above is listed as UU. > > The motherboard is known to have problems with chained IRQs, so the latest > Ubuntu kernels use independent IRQs to avoid an interrupt storm on IRQ 7. > > Apart from that, let me know what else I should test. David, thanks for the report. Just to be clear, I didn't report the original issue, I merely attempted to repro it on a Sandy Bridge quad core. I'm the original cx23885/8 Linux driver developer, so I know the hardware well and have a vested interested in chasing down any obvious problems. I was unable to repro the issue. That being said, another user reported success after disabling VT-d/VT-x. Have you tried that? - Steve -- Steven Toth - Kernel Labs http://www.kernellabs.com
