Re: [PATCH v4 1/7] accel/ivpu: Introduce a new DRM driver for Intel VPU

From: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: Krystian Pradzynski <krystian.pradzynski@linux.intel.com>,
	Jeffrey Hugo <quic_jhugo@quicinc.com>,
	dri-devel@lists.freedesktop.org,
	Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>,
	tzimmermann@suse.de, andrzej.kacprowski@linux.intel.com
Subject: Re: [PATCH v4 1/7] accel/ivpu: Introduce a new DRM driver for Intel VPU
Date: Fri, 6 Jan 2023 13:43:25 +0100	[thread overview]
Message-ID: <20230106124325.GC1586324@linux.intel.com> (raw)
In-Reply-To: <CAKMK7uEu=aKCVgNfzqVE-NKX9O6HyNmYKORuHcK4Y=j=kmRDMw@mail.gmail.com>

On Fri, Jan 06, 2023 at 11:44:58AM +0100, Daniel Vetter wrote:
> > > The problem is going to happen as soon as you have cross-vendor userspace.
> > > Which I'm kinda hoping is at least still the aspiration. Because with
> > > cross-vendor userspace you generally iterate & open all devices before you
> > > select the one you're going to use. And so we do kinda need a distinction,
> > > or we need that the single-user drivers also guarantee that open() is
> > > cheap.
> >
> > FWIW we had good support in ivpu for probe open's in form of lazy context
> > allocation. It was removed recently due to review feedback that this is
> > unnecessary, but we can add it back.
> 
> Yeah once you have more than 1 multi-user accel chip in the system you
> need to do that. Which is really the reason why I think smashing
> multi-user client accel things into render is good, it forces drivers
> to suck less.
> 
> On that topic, does your userspace still do the drmIoctl() wrapper?

Yes, it still does. We released the code BTW, the wrapper can be seen here:
https://github.com/intel/linux-vpu-driver/blob/b6ed73cabf87f461cbbe4427e1b9351a548d790b/umd/vpu_driver/source/os_interface/vpu_driver_api.cpp#L41

Regards
Stanislaw