The Current State Of The Intel "Crocus" Gallium3D Driver

[phoronix]

Phoronix: The Current State Of The Intel "Crocus" Gallium3D Driver

The Intel "Crocus" Gallium3D driver in development for supporting old Intel i965 IGPs through Haswell continues making progress by the upstream, open-source Mesa3D community for hopefully one day replacing Intel's classic "i965" Mesa driver...

https://www.phoronix.com/scan.php?page=news_item&px=Intel-Crocus-April-2021-State

[MadCatX]

If only Intel went with Gallium3D from the get go instead of arguing that it is too complicated and slow. Now we will end up with yet another community developed driver for HW that is still widely used.

[geearf]

Why is this a forked driver and not part of Iris? Are the architecture too different to have them in one driver?

[ms178]

I hope Crocus will be as feature rich and at least as fast as the classic driver, that would extend the usefulness of my Sandy Bridge laptop quite a bit. But that would mean OpenGL 3.3 support. Hopefully they will test it well, I don't want to see stability suffering from this move either. But at least Sandy Bridge doesn't seem to be the focus for now, at least from Dave's blog post it reads that it is the least tested of all.

[Leopard]

Why is this a forked driver and not part of Iris? Are the architecture too different to have them in one driver?

Because Intel devs are not working on Crocus at any capacity, so they just wanted Broadwell and newer to have Iris.

Crocus is a community effort.

Main dev working on it is a Red Hat employee, other one is an ex (?) Nouveau dev.

That is why it is not upstream. Intel didn't want to work on/bother with those older gen gpu's initially.

Which in result you actually got a very inferior experience on Linux with some of those gpu's compared to Windows. With Ironlake for example.

Those gpu's supports D3D10 on Windows but stuck at GL 2.1 on Linux which GL 2.1 is not counter part of D3D10 feature wise.

https://www.phoronix.com/scan.php?page=news_item&px=MTMxMDQ

[Leopard]

I hope Crocus will be as feature rich and at least as fast as the classic driver, that would extend the usefulness of my Sandy Bridge laptop quite a bit. But that would mean OpenGL 3.3 support. Hopefully they will test it well, I don't want to see stability suffering from this move either. But at least Sandy Bridge doesn't seem to be the focus for now, at least from Dave's blog post it reads that it is the least tested of all.

Classic driver is on life support. And still regresses now and then, despite that and as it is in low importance area getting fixes for that is very unlikely compared to how fast you can get a fix on newer driver.

Don't need to worry, upstream Mesa won't accept a driver that is in really bad shape and make it default to everyone until it is battle tested.

[oiaohm]

Which in result you actually got a very inferior experience on Linux with some of those gpu's compared to Windows. With Ironlake for example.

Those gpu's supports D3D10 on Windows but stuck at GL 2.1 on Linux which GL 2.1 is not counter part of D3D10 feature wise.

https://en.wikichip.org/wiki/intel/h...hics_(ironlake)
Ironlake is Westmere Intel did rename Ironlake to Westmere officially. Under windows Ironlake/Westmere what ever you want to call it only had opengl 2.1 even under windows so your opengl experience with Windows is no better than Linux here.
https://www.phoronix.com/scan.php?pa...tem&px=MTMxMDQ

Does not cover how you would have to implement opengl 3.0. Problem here there is extra acceleration silicon in Sandy Bridge contains stuff particularly for opengl 3.0.

Horrible part here is DX10.0 feature greater than GL 2.1 but feature less than GL 3.0. CPU emulating missing GPU features to get up to opengl 3.0 on the Ironlake/Westmere may not turn out that great. This is a case where if you had mesa had a functional DX10 instead of just a DX9 interface this would be helpful.

Opengl 3.3 on Sandy Bridge that is 6th gen can do a reasonable fist of DX10.1. 7th gen is the start of Vulkan on Linux.

Yes also if you look it up the Ironlake/Westmere is only Dx feature level 10.0 in hardware was using DX10 included software emulation to expose DX 10.1 to applicactions. This kind of explains why even under windows why there is a huge performance gap between Sandy Bridge and Ironlake/Westmere as Sandy Bridge is full DX 10.1 feature level in hardware.

Please also note large section of Gen 4 Intel hardware is also feature level DX 10.0 without the Intel driver turning on software emulation to take that up to 10.1. Yes that hardware also only exposed only opengl 2.1 and 2.0.

Gen 5 and Gen 5.5 Ironlake/Westmere really was not that much of a improvement over Gen4 major thing was about Gen5 is that is moved into the cpu instead of being in the chip-set. Gen 4 and Gen 5 owners of those should not be expecting much improvement because that hardware is not that great in silicon. Really don't have that much CPU performance to trade to fix the issues.

[reba]

Has anything being said about merging Crocus back to Iris?

[M@GOid]

I for one appreciate the effort on this driver.

Today a good shape OpenGL driver isn't used only for games, but on desktop rendering too. I have 3 systems still running on Ivy Bridge hardware, and the price hikes of the last year will force me to stick with them for some years to come.

[ermo]

This feels like amdgpu support w/GCN 1/2/3 all over again. Still super pleased that it's happening, as I have both Westmere, SB, IB and Haswell hardware still.

Thank you to Mr. Airlie (et al.) and RH for deciding to develop/sponsor this.