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On Sunday, 19 January 2020 15:02:36 GMT edes wrote: |
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> el 2020-01-18 a las 12:58 edes escribió: |
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> > But now for some reason it works as playback device, but is not |
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> > recognized as capture device. |
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> |
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> I kept investigating, and all the evidence points to a kernel problem |
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> (gentoo-sources). |
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> |
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> I tried several versions, everything works fine with kernels up to 5.4.10, |
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> problems appear with 5.4.11, 12 and 13. Same results on two different |
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> machines with two different cards (same model). |
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> |
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> It seems that some changes were introduced in 5.4.11 that affect USB |
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> audio. This only affects my Sound Devices USPre2 cards, I tried with a |
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> cheap card, and it continues to work normally with all kernels. |
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> |
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> Where should I report this problem and who could help? |
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> |
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> Thanks. |
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> |
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> |
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> -- |
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You could compare the dmesg output of working and non-working kernels and see |
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what differences are present, then google for bugs/solutions on that basis. |
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You could also diff the two different kernel tree versions and see what |
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drivers have changed. Also, check the kernel git repo to see what the |
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changelog reports, which could narrow down the diff'ed files: |
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https://github.com/torvalds/linux |
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You could post a bug in BGO, but the devs may ask you to enable/undertake |
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kernel debugging, which is not a 5 minute job and/or use vanilla kernel |
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sources and report it upstream, depending on how rare this problem is and if |
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they have been bitten by the same bug themselves. |
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https://wiki.gentoo.org/wiki/Kernel_Crash_Dumps |
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https://www.oreilly.com/library/view/linux-device-drivers/0596005903/ch04.html |
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-- |
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Regards, |
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|
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Mick |
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