Hi Manuel, all
On Tue, Sep 01, 2026 at 06:52:55AM +0200, Salvatore Bonaccorso wrote:
> Control: tags -1 + moreinfo
>
> Hi,
>
> On Mon, Aug 31, 2026 at 10:41:47AM -0500, Manuel R. Buffa wrote:
> > Package: src:linux
> > Version: 6.12.107-1
> > Severity: important
> > X-Debbugs-Cc: [email protected]
> >
> > Dear Maintainer,
> >
> > I am reporting a reproducible amdgpu/VCE regression on Debian 13 (trixie)
> > with an AMD Radeon RX 480 / Polaris10 GPU. Active RustDesk remote-control
> > sessions are stable on Debian kernel 6.12.101-1 but trigger a VCE ring
> > timeout
> > and GPU reset on 6.12.105-1 and 6.12.107-1.
> [...]
>
> As you can reproduce your issue reliably, please bisect the changes
> between 6.12.101 and 6.12.105 to identify the breaking commit. That
> given we can have a look if it is a known regression already or needs
> to be reported upstream yet.
>
> Let me know if you need instructions for the bisecting steps!
Manuel asked off-bug about the instructions, so here we go. To bisect
between 6.12.101 and 6.12.105 proceed as follows (once you have the
my_config, compilation could be as well on a more powerful machine).
git clone --single-branch -b linux-6.12.y
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git
cd linux-stable
git checkout v6.12.101
cp /boot/config-$(uname -r) .config
yes '' | make localmodconfig
make savedefconfig
mv defconfig arch/x86/configs/my_defconfig
# test 6.12.101 to ensure this is "good"
make my_defconfig
make -j $(nproc) bindeb-pkg
... install the resulting .deb package and confirm problem does not exist
# test 6.12.105 to ensure this is "bad"
git checkout v6.12.105
make my_defconfig
make -j $(nproc) bindeb-pkg
... install the resulting .deb package and confirm problem exists
With that confirmed, the bisection can start:
git bisect start
git bisect good v6.12.101
git bisect bad v6.12.105
In each bisection step git checks out a state between the oldest
known-bad and the newest known-good commit. In each step test using:
make my_defconfig
make -j $(nproc) bindeb-pkg
... install, verify if problem exists
and if the problem is hit run:
git bisect bad
and if the problem doesn't trigger run:
git bisect good
. Please pay attention to always select the just built kernel for
booting, it won't always be the default kernel picked up by grub.
Iterate until git announces to have identified the first bad commit.
Then provide the output of
git bisect log
In the course of the bisection you might have to uninstall previous
kernels again to not exhaust the disk space in /boot. Also in the end
uninstall all self-built kernels again.
Regards,
Salvatore
