dmar, dma_pool, etc

[Niclas Zeising]

On 2019-04-29 18:56, Johannes Lundberg wrote:
> On 4/29/19 3:41 PM, Tycho Nightingale wrote:
>> For the GPU it’s important to note that enabling the IOMMU didn’t work before, was not a goal of this error, and would be expected to not work right now.  However, it’s possible this change revealed some cases where some DMAR functionality was enabled in the BIOS and since the support is incomplete breakage is happening.  Or something else that I am overlooking right now.
> 
> Especially i915's GEM (i915_gem.c) have a lot of FreeBSD specific
> patches related to memory. Any FreeBSD code in drm drivers is within
> #ifndef __linux__  tags so it's easy locate our patches.
> 
> It could also be some inconsistency between linuxkpi in base and
> linuxkpi gplv2 in ports.
> 
> I don't think disabling options in BIOS in the correct solution. This
> would also disable functionality for virtual machines.

Agreed.  This has to work with virtualization options enabled in BIOS. 
We can't expect people to fiddle with BIOS settings just to get FreeBSD 
graphics to work, especially not virtualization, which is a very common 
use case as well.
Regards
-- 
Niclas Zeising
FreeBSD Graphics Team