Since kernel 5.9.1: After resume vlc cannot display dvb-t. I can not find any logfile, which shows the issue, but the workaround is: disconnect the usb-stick, wait a minute, connect it again, then it works again. The needed kernel-modules are: dvb-demod-si2168-b40-01.fw and dvb-demod-si2168-b40-01.fw USB-HW is: August DVB-T210 - DVB-T USB TV Stick After a normal boot it is always working. When I went back to kernel 5.9.0: There is no issue.
I think, that this patch may cause the issue: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v5.9.2&id=1eaed405fcd22e52a438b619e6ea85539f1c150a So I added Oliver Neukum to the CC. Maybe he could be interested in this issue.
Created attachment 293329 [details] no dvb-t after resume More testing figured out that kernel mainline 5.9.x is affected. The issue occurs not always after the first resume, often seems to occur after the second resume. There are two attachments from dmesg. dmesg 5.9.0.txt shows, what happens after the second resume, when dvb-t is not working. dmesg 5.9.0 after reconnecting.txt shows, what happens after disconnecting and reconnecting the usb-stick, when dvb-t is working again. I have the guess, that this issue comes up, when the PC was disconnected from power and then resume starts again.
Created attachment 293331 [details] dvb-t working after reconnecting usb-stick
*** This bug has been marked as a duplicate of bug 201467 ***
Reopened because the comment of bug 201467 fits to this bug, but not the bug itself. The cause of this bug affects all older, other kernels. I tested 4.8.6 and 4.8.10, which definitely had a working dvb-t after resume earlier, when 4.8.x was mainline. Today they do have this issue too. Dmesg shows always, that only one fw-file loaded, instead of two. Some years ago the workaround of a similar issue was, to build a kernel with build-in firmware. But this fails too now.
This makes dvb-t work again: # rmmod dvb_usb_dvbsky # modprobe dvb_usb_dvbsky