FreeBSD Is Pursuing A Compatibility Layer To Make It Easier To Run Linux DRM Drivers

[phoronix]

Phoronix: FreeBSD Is Pursuing A Compatibility Layer To Make It Easier To Run Linux DRM Drivers

While for years developers working on FreeBSD have been porting DRM/KMS driver changes from the Linux kernel over to their kernel, they have trailed greatly behind the mainline Linux kernel driver state due to the amount of changes they have been making to the driver when re-basing it against a new Linux kernel release. Now they are pursuing a new approach of using a compatibility layer where they hope to be able to more closely follow the upstream Linux DRM/KMS drivers...

http://www.phoronix.com/scan.php?page=news_item&px=FreeBSD-DRM-KMS-Layer

[danieru]

This sounds great!
So it will be possible to have nouveau or AMDGPU on FreeBSD?

[starshipeleven]

Netflix seems very interested in FreeBSD lately. Have they adopted it or something?

Anyway, I hope other Unixes adopt this layer too, their graphics support is getting stupidly outdated.

[pal666]

it seems they call it "kms" or "drm" when in reality it is "i915"
best linux compatibility layer is linux

[Chewi]

Netflix seems very interested in FreeBSD lately. Have they adopted it or something?

I gather they've always used it on their servers. Don't know why they're interested in graphics drivers though.

[Luke_Wolf]

it seems they call it "kms" or "drm" when in reality it is "i915"
best linux compatibility layer is linux

Not quite, so linuxkpi is a FreeBSD kernel driver shim for the Linux Kernel Driver API originally created by OFED for their infiniband driver, the graphics team is using and extending this shim so that they can get up to date again and keep the diffs between Linux and FreeBSD graphics as small as possible, so that they can stay that way.

see: https://reviews.freebsd.org/D3182

Yes it's just the i915 driver for now by all indications, but at the same time if their compat shim is good enough to get one of the graphics drivers working with kernel, there's probably not a whole lot more work on the shim required for the other drivers.

Netflix seems very interested in FreeBSD lately. Have they adopted it or something?

Anyway, I hope other Unixes adopt this layer too, their graphics support is getting stupidly outdated.

Netflix has a huge investment in FreeBSD for their CDN, it's entirely possible that they've begun to evaluate/adopt it internally for their workstations, but... I find it more likely they're continuing to be "Good Citizens", with possible some personal interests from a few individuals inside the company.

[SystemCrasher]

it seems they call it "kms" or "drm" when in reality it is "i915"
best linux compatibility layer is linux

Wrong. KMS and DRM are Linux terms, Intel has pioneered doing so, but as far as I can see, these days devs are trying to keep DRM/KMS generic enough and if you'll take a look around, there're quite many drivers gone for it, it has gone as far as to idea to prohibit adding new drivers if they are not using DRM/KMS thing. Basically it is like a deprecating fbdev and somesuch. E.g. AMD's bridgman has insisted it should be okay even for simplest LCDs. While I'm not really sure it is not an overkill (I'm yet to see example of such driver being small and simple), overall it seems quite generic and even Intel devs care about keeping it this way. So FreeBSD devs have some point. Thoguh best compatibility layer is Linux kernel itself

[pal666]

KMS and DRM are Linux terms

i know what they mean, i was referring to the fact that freebsd doesn't support kms or drm drivers in general, it supports one intel driver

[Luke_Wolf]

i know what they mean, i was referring to the fact that freebsd doesn't support kms or drm drivers in general, it supports one intel driver

Ehm... https://wiki.freebsd.org/Graphics

They also support Radeon. It's just that their support is wildly out of date because they made a lot of work for themselves by trying to adapt the kernel drivers to FreeBSD, hence the mentioned 9k diff they were starting out with, which with linuxkpi is apparently down to 450 lines for i915

https://lists.freedesktop.org/archives/intel-gfx/2016-May/095640.html

Given he apparently went from 3.8 -> 4.6 in 3 weeks for i915 it's quite likely that they'll switch Radeon over to using linuxkpi and bring it to speed and bring in AMDGPU (and possibly nouveau) within similar spans.

[SystemCrasher]

i know what they mean, i was referring to the fact that freebsd doesn't support kms or drm drivers in general, it supports one intel driver

They also support old (VLIW-based) radeons. But I would agree it is a shame their wiki e.g. suggests to use BLOBs for nvidias. So much for opensource, dammit.