Bug 105226 - [anv] vulkaninfo > Haswell Vulkan support is incomplete
Summary: [anv] vulkaninfo > Haswell Vulkan support is incomplete
Status: RESOLVED INVALID
Alias: None
Product: Mesa
Classification: Unclassified
Component: Drivers/Vulkan/intel (show other bugs)
Version: git
Hardware: x86-64 (AMD64) Linux (All)
: medium normal
Assignee: Intel 3D Bugs Mailing List
QA Contact: Intel 3D Bugs Mailing List
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Reported: 2018-02-23 11:43 UTC by Darius Spitznagel
Modified: 2018-02-23 18:56 UTC (History)
1 user (show)

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Description Darius Spitznagel 2018-02-23 11:43:32 UTC
Hello devs,

what exactly is missing for Haswell to show full vulkan support?
And if a feature/extension is missing is someone working on it?
Comment 1 Mark Janes 2018-02-23 18:20:09 UTC
My understanding is that HSW is lacking hardware features.
Comment 2 Jason Ekstrand 2018-02-23 18:56:14 UTC
(In reply to Mark Janes from comment #1)
> My understanding is that HSW is lacking hardware features.

That's not quite true.  I believe Haswell is capable of doing everything required for Vulkan but there are some corner cases it doesn't quite handle right.  In particular:

 1) Haswell doesn't support stencil texturing
 2) Haswell border colors are bizarrely format-dependent and some sort of shader work-around would be neede for them to work correctly.
 3) vkCmdWaitEvents is not implemented because Haswell lacks a memory-based MI_SEMAPHORE_WAIT.  This could probably be worked around by doing a busy-loop in the command streamer.

On Ivybridge and Bay Trail, there are a couple other issues:

 4) No support for texture swizzle so channel orderings just don't work.
 5) Integer border color basically doesn't work at all.  The only fix is very painful shader workarounds.

That's all I know of off-hnand and it's probably all fixable.  However, we (Intel) have no commitment to Vulkan on Haswell hardware and earlier beyond trying to avoid breaking it further.  If some community member wants to take on an item on that TODO list, I'd be happy to review and help land the patches but they're all fairly annoying things to fix.  (I've already fixed all the easy stuff.)


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