Skylake Iris 540 renderer string in i965 (the same as HD 520)

[Ben Widawsky]

On Thu, Mar 31, 2016 at 01:26:57PM -0700, Ben Widawsky wrote:
> On Tue, Mar 29, 2016 at 09:00:14PM +0200, Michal Powalko wrote:
> > Dear Ben and Michal,
> > dear Ubuntu-bugsquad,
> > 
> > I have recently bought a new Skylake based NUC with Intel® Core(TM) i5-6260U
> > processor and Intel® Iris(TM) graphics 540. I am working on Ubunut 14.04.3
> > LTS (kernel 4.2) and waiting for 16.04 (kernel 4.4) to take advantage of
> > both CPU (from Linux kernels > 4.3) and GPU full support. The 16.04 beta 2
> > is quite "unstable" in terms of Skylake GPU (see e.g. the archlinux source),
> > so I tried to find out the walk-around to make it work more stable...
> > 
> > I have found out Mesa  commit "i965/skl: Update Skylake renderer strings"
> > describing the device ID's of different GPU's. In case of my NUC, according
> > the ARK' info Iris 540 has the ID of 0x1916, which in Mesa 11.x file has
> > associated with HD 520 :( I did some research and found out, that the ID of
> > 0x1916 can be used for HD 520 and Iris 540 (see attached screen-shots and
> > links below) depending on the CPU :/
> > 
> > 1. Would it be possible for You to find out the solution to assign the
> >    proper GPU name base on ID (Iris 540 in case of i5-6260U) -  maybe
> >    using CPU info ?
> > 2. Can the wrong name / feature assessment between HD 520 and Iris 540
> >    be the source of unstable operation / freeze / crash of the system
> >    (system working well but slow with Gallium3Ddriver)?
> > 
> > I would be really happy to help You providing more information if necessary.
> > 
> > Sources:
> > 
> >  * Mesa commit
> >    https://cgit.freedesktop.org/mesa/mesa/commit/?h=11.2&id=20e8ee36627f87414440650dcff89990eb70c688
> > 
> >  * Wiki is saying:  Iris Graphics 540, *GT3e* - 48 execution units with
> >    64 MB of eDRAM, up to 806.4 GFLOPS at 1.05 GHz
> >    https://en.wikipedia.org/wiki/Intel_HD_and_Iris_Graphics
> >    https://en.wikipedia.org/wiki/List_of_Intel_graphics_processing_units
> > 
> >  * Intel graphics on linux
> >    https://wiki.archlinux.org/index.php/intel_graphics
> > 
> >  * NUC specification
> >    http://www.intel.com/content/www/us/en/nuc/nuc-kit-nuc6i5syh.html
> > 
> >  * Intel Gen9 HD Graphics
> >    http://www.anandtech.com/show/9582/intel-skylake-mobile-desktop-launch-architecture-analysis/6
> > 
> > 
> > Best regards from Denmark
> > Michal Powalko
> > 
> > 
> 
> 
> Thank you for bringing this to my attention. Summing up there are two products
> with the same devid, but different branding.
> 520: http://ark.intel.com/products/88192/Intel-Core-i7-6600U-Processor-4M-Cache-up-to-3_40-GHz
> 540: http://ark.intel.com/products/91160/Intel-Core-i5-6260U-Processor-4M-Cache-up-to-2_90-GHz
> 
> Let me look into this further, and I will see what we can do. Meanwhile, I would
> advise filing a bug upstream on freedesktop.org.
> 

Hi. Ark has been updated to reflect the correct PCI device ID. I don't have an
actual device, so I can't confirm this.

-- 
Ben Widawsky, Intel Open Source Technology Center