Yeah, this is on the list. See: https://bugzilla.kernel.org/show_bug.cgi?id=219383#c5 I had a fix for the AMD boot-time issue already over a month ago but unfortunately took time to get enough feedback. BR, Jarkko On Fri Oct 25, 2024 at 3:11 AM EEST, Christian Heusel wrote: > Hello everyone, > > Adam reports that since switching to the 6.10 kernel they have a popping > sound from time to time (roughly every 10 minues) on their headphones > which are connected via a [UGREEN's 5-in-1 USB-C Hub][0]. > > We have then done a [lengthy bisection][1] on the mainline kernel which > came to the conclusion that the following commit is the culprit of the > issue: > > 1b6d7f9eb150 ("tpm: add session encryption protection to tpm2_get_random()") > > Since I thought that these results are likely not correct Adam has > verified our results again by re-testing the bisection steps and again > came to the same conclusion. Additionally I have shot the same question > [at Jarkko on Mastodon] to find out if it's possible that changes in the > TPM subsystem can have such an effect.. Without knowing the exact commit > we had bisected to he pointed to the same functionality: > > > Jarkko Sakkinen (@jarkko@xxxxxxxxxxxxxxxxx): > > > > @gromit i might actually might have hunch for this but have been > > unmotivated to move forward before these patches are merged. One thing > > at a time IMHO, especially with performance fixes. > > NOTE: this is a hyphothesis. > > > > tpm2_get_random() needs to be reconsidered with encryption as hwrng > > calls it often enough and there's now more overhead. > > > > It pulls entropy in small chunks subtracting the length in the look > > like you would use read() syscall from user space. This is not right. > > This leads to small and variable size exchanges and yeah generally > > that equates to an inefficient implemenation with bad latency > > properties. > > If there are any patches to test or if further input is needed from the > initial reporter on our Bugtracker we can do that! > > Thank you all for your hard work on the kernel! > > Cheers, > Chris > > > [0]: https://uk.ugreen.com/collections/hubs-1/products/ugreen-5-in-1-4k-hdmi-usb-c-hub > [1]: https://gitlab.archlinux.org/archlinux/packaging/packages/linux/-/issues/79#note_210599 > [2]: https://chaos.social/@gromit/113345582873908273 > > --- > #regzbot introduced: 1b6d7f9eb150 > #regzbot link: https://gitlab.archlinux.org/archlinux/packaging/packages/linux/-/issues/79 > #regzbot link: https://chaos.social/@gromit/113345582873908273 > #regzbot title: tpm: popping sound in headphones connected via USB-C
