drm-fbsd11.2-kmod on 12

[Niclas Zeising]

On 2019-11-07 23:00, Matthew D. Fuller wrote:
> On Thu, Nov 07, 2019 at 09:41:20AM +0100 I heard the voice of
> Niclas Zeising, and lo! it spake thus:
>>
>> What issues are you seeing with the 4.16 branch?  Have you reported
>> this?
> 
> On one machine with radeonkms and a Radeon 6450, it will eventually
> crash when using vdpau output for videos (I believe even with formats
> that don't get hardware accelerated).  It doesn't happen
> deterministically, but on a frequency of maybe a few percent of the
> time.  4.11 is perfectly fine with it, and 4.16 hasn't shown any
> surprises without vdpau, so that's reasonably easily workaroundable in
> practice.
> 
> On my main workstation, with amdgpu and a Radeon wx2100 (roughly
> 550-something-ish), it will crash out without obvious trigger, on the
> order of maybe twice a week.  Playing video, not playing video,
> scrolling in a browser, not scrolling in a browser, xlock'd and DPMS'd
> off, everything on, etc.  As I recall, backtraces wound up pointing at
> not much after ioctl handlers, bearing some resemblance to the stuff
> in GH issue #149 (though I'm on the different driver), and I believe
> once that looked more like #130 with the ttm funcs (with similar to
> both showing up in the BZ bug linked from there).  I don't have any of
> the cores still around though; I switched back to 4.11 last year, and
> it's been solid since.
> 
> 
> Part of the difficulty with this being so much upstream-y code that
> we're a ways behind on, is that I know it can be really hard to
> separate "we cause this problem by a mistake in porting" vs "this is a
> bug in the pure code" (especially of the "... and is fixed in later
> upstream versions already" variant).  So I figure the best way to get
> it fixed is to desperately strive to not distract the people trying to
> catch up to upstream, and more up-to-date-ish upstream code will
> either have fixed their bug, or make it more certain that it's
> something on our side causing it.  Either way, there's more to work
> with than "it crashes every couple days"...

Can you please report this on the FreeBSDDesktop github.
> 
> 
>> Getting 4.11 running on FreeBSD 12.1 would require some effort, and
>> I believe that effort is much better spent elsewhere.
> 
> I figured it would actually be relatively simple; it works fine with a
> mid-July stable/12, and there's only a half dozen or so commits on the
> drm-v4.16-fbsd12.0 branch since then, so I expect I can probably get
> it working just by backporting a couple of them.  (I _was_ asking "has
> anybody who knows this code already done this work?", more than "hey,
> can you guys do this for me?")

I don't know if it is simple or not.  The code is there, if you can get 
it running on 12.1 without breaking 11.3, then, by all means do it.
Regards
-- 
Niclas Zeising