Re: loading drm crashes system

On Tue, 26 Jan 2021 13:42:45 +0100 Emmanuel Vadot
<manu_at_bidouilliste.com> wrote:
> On Tue, 26 Jan 2021 07:02:11 +0000
> Alexey Dokuchaev <danfe_at_freebsd.org> wrote:
>> On Mon, Jan 25, 2021 at 10:21:16PM -0500, Robert Huff wrote:  
>>> Niclas Zeising asks:  
>>>> When did it stop working?  
>>> 
>>> September ... I _think_.  
>> 
>> Yeah, that sounds about right.
>> 
>> There are known issues with Radeon cards, they were quite well supported
>> a year ago, then something got broken.  I've promised to bisect this and
>> find the cause, but there were several syscall-related changes in -CURRENT
>> though the course of the last year, so bisecting just the kernel is not
>> enough (machine won't get to login prompt if the userland does not match),
>> which cripples the process.
>> 
>> I still intend to take this quest, just not sure when. :(
> 
>  So back in November I applied a few commits from tijl_at_ related to
> radeon and i386 (added to cc) :
> https://github.com/freebsd/drm-kmod/commits/5.4-lts?author=tijl_at_coosemans.org
> 
>  For me this fixed radeon so that gives some timeline if someone with
> non working hardware wants to bisect.
>  I know that bisecting drm-kmod is somewhat hard as you always need
> matching kernel code when we update it to use some new functionality in
> base linuxkpi but there is nothing that I can do about it.
>  It might work and be quicker to only bisect the kernel with a
> stable/12 userland (no need to recompile) so I would start by testing a
> kernel from early november and same date for drm-kmod.
> 
>  Tijl since you also reported a build failure a few days/weeks ago for
> radeon can you report if your radeon card works ? (And which one it is).

My card works (14.0-CURRENT from last Sunday) but it is an old radeon
9700 from 2004 so it doesn't have any fancy modern features and uses
only a small part of the radeon driver.