Hi Mauro,
the last two commits on drivers/media/usb/dvb-usb-v2/dvbsky.c have negative
effects on the operation of the DVBSky T680CI. With kernel 4.18-rc6, but
commits 7d95fb746c4eece67308f1642a666ea1ebdbd2cc and
14f4eaeddabce65deba2e1346efccf80f666f7b7 undone the device works.
Commit 14f4eaed ("media: dvbsky: fix driver unregister logic") causes the
following:
After disconnecting the T680CI /dev/dvb/adapter0/frontend0 still exits. So, if
connected again it cannot create a frontend:
[ 560.756035] usb 2-3: new high-speed USB device number 4 using xhci_hcd
[ 561.100030] usb 2-3: dvb_usb_v2: found a 'DVBSky T680CI' in warm state
[ 561.100205] usb 2-3: dvb_usb_v2: will pass the complete MPEG2 transport
stream to the software demuxer
[ 561.100220] dvbdev: DVB: registering new adapter (DVBSky T680CI)
[ 561.101426] usb 2-3: dvb_usb_v2: MAC address: xx:xx:xx:xx:xx:xx
[ 561.109404] i2c i2c-8: Added multiplexed i2c bus 9
[ 561.109410] si2168 8-0064: Silicon Labs Si2168-B40 successfully identified
[ 561.109414] si2168 8-0064: firmware version: B 4.0.2
[ 561.112485] si2157 9-0060: Silicon Labs Si2147/2148/2157/2158 successfully
attached
[ 561.119145] sp2 8-0040: CIMaX SP2 successfully attached
[ 561.119161] usb 2-3: DVB: registering adapter 0 frontend 0 (Silicon Labs
Si2168)...
[ 561.119174] sysfs: cannot create duplicate filename '/class/dvb/
dvb0.frontend0'
[ 561.119178] CPU: 0 PID: 17859 Comm: kworker/0:2 Not tainted 4.18.0-rc6 #1
[ 561.119180] Hardware name: LENOVO 20BWS49800/20BWS49800, BIOS JBET70WW
(1.34 ) 06/15/2018
[ 561.119186] Workqueue: usb_hub_wq hub_event
[ 561.119189] Call Trace:
[ 561.119197] dump_stack+0x46/0x5b
[ 561.119202] sysfs_warn_dup+0x51/0x60
[ 561.119207] sysfs_do_create_link_sd.isra.2+0x87/0xa0
[ 561.119210] device_add+0x2c9/0x630
[ 561.119214] device_create_groups_vargs+0xd8/0xe0
[ 561.119218] device_create+0x44/0x60
[ 561.119223] ? _cond_resched+0x10/0x40
[ 561.119228] ? kmem_cache_alloc_trace+0x159/0x160
[ 561.119234] dvb_register_device+0x21f/0x2b0 [dvb_core]
[ 561.119240] dvb_register_frontend+0x18c/0x220 [dvb_core]
[ 561.119246] ? dvb_usbv2_probe+0xb55/0x11b0 [dvb_usb_v2]
[ 561.119249] dvb_usbv2_probe+0xb55/0x11b0 [dvb_usb_v2]
[ 561.119254] usb_probe_interface+0xfc/0x300
[ 561.119258] driver_probe_device+0x2ec/0x4c0
[ 561.119261] ? __driver_attach+0x110/0x110
[ 561.119263] bus_for_each_drv+0x61/0xa0
[ 561.119267] __device_attach+0xd4/0x150
[ 561.119270] bus_probe_device+0x85/0xa0
[ 561.119273] device_add+0x40b/0x630
[ 561.119276] usb_set_configuration+0x4fb/0x8a0
[ 561.119281] generic_probe+0x23/0x70
[ 561.119284] driver_probe_device+0x2ec/0x4c0
[ 561.119287] ? __driver_attach+0x110/0x110
[ 561.119289] bus_for_each_drv+0x61/0xa0
[ 561.119292] __device_attach+0xd4/0x150
[ 561.119295] bus_probe_device+0x85/0xa0
[ 561.119297] device_add+0x40b/0x630
[ 561.119301] usb_new_device+0x1b3/0x3d0
[ 561.119305] hub_event+0x7a2/0x16e0
[ 561.119310] process_one_work+0x1cf/0x3f0
[ 561.119314] worker_thread+0x28/0x3c0
[ 561.119317] ? set_worker_desc+0xb0/0xb0
[ 561.119321] kthread+0x10e/0x130
[ 561.119326] ? kthread_create_worker_on_cpu+0x70/0x70
[ 561.119329] ret_from_fork+0x35/0x40
[ 561.119351] dvbdev: dvb_register_device: failed to create device
dvb0.frontend0 (-17)
[ 561.148038] rc_core: IR keymap rc-dvbsky not found
[ 561.148040] Registered IR keymap rc-empty
[ 561.148101] rc rc0: DVBSky T680CI as /devices/pci0000:00/0000:00:14.0/
usb2/2-3/rc/rc0
[ 561.148171] input: DVBSky T680CI as /devices/pci0000:00/0000:00:14.0/
usb2/2-3/rc/rc0/input17
[ 561.148345] usb 2-3: dvb_usb_v2: schedule remote query interval to 300
msecs
[ 561.148351] usb 2-3: dvb_usb_v2: 'DVBSky T680CI' successfully initialized
and connected
With commit 7d95fb74 ("media: dvbsky: use just one mutex for serializing
device R/W ops") scanning and watching/recording of DVB-T2 channels doesn't
work anymore (DVB-T/C not tested). Recordings are just empty files. dvbv5-scan
outputs the following:
$ dvbv5-scan dvb_channel.conf
Cannot calc frequency shift. Either bandwidth/symbol-rate is unavailable
(yet).
Scanning frequency #1 498000000
Lock (0x1f) Signal= -49,00dBm C/N= 27,25dB UCB= 0 postBER= 80,2x10^-3
ERROR dvb_read_sections: no data read on section filter
ERROR error while waiting for PAT table
Scanning frequency #2 578000000
Lock (0x1f) Signal= -48,00dBm C/N= 32,75dB UCB= 0 postBER= 1,00
ERROR dvb_read_sections: no data read on section filter
ERROR error while waiting for PAT table
..
I also noticed that the module m88ds3103 is loaded automatically whenever the
module dvb_usb_dvbsky is loaded. However, m88ds3103 is a DVB-S/S2 demodulator
driver, but the T680CI is a DVB-T/T2/C device. Is there a reason why it is
loaded automatically? Maybe because the dvbsky driver was written for S960/
S860 in the first place and support for T680CI was added later?
Could you please look into this? Thank you.
There is also a discontinuity issue with this device when a CAM is
initialized. However, I'll address that later.
Peter
