Softlockup on boot with Cape Verde XT on many kernels

[Alex Deucher]

On Sat, Jan 10, 2015 at 8:58 PM, Federico <federicotg at gmail.com> wrote:
> Hi.
> I always get a soft lockup when booting since I bought a Cape Verde XT
> [Radeon HD 7770/8760 / R7 250X].
>
> In this bug report you can find screenshots of the softlockup and the kernel
> panic generated by using softlockup_panic=1
>
> https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/1386973
>
> I have this problem with and without nomodeset and I have tested the kernels
> that come with Ubuntu 14.04, 14.10 and 15.04 (today's daily image).
>
> The live session shows me the boot menu where I can enter kernel  options
> and such, but when booting into a live session it soon prints the softlockup
> messages forever.
>
> In order to install catalyst I had to disable the card in the BIOS and boot
> into the integrated graphics. Catalyst works perfectly.
>
> MoBo is based on AMD 780G (Radeon HD3200 IGP).
>
> If there's anything I can do to help find a workaround or a fix for this,
> let me know.

Booting with nomodeset disables the graphics drivers so if you are
still getting problems, it may a hardware problem.  Can you attach
your full dmesg and lspci output?  Are you disabling the onboard
graphics when enabling the external dGPU?

Alex