[PATCH 0/3] drm/amdgpu: implement raster configuration

[Deucher, Alexander]

> -----Original Message-----
> From: Michel Dänzer [mailto:michel at daenzer.net]
> Sent: Monday, September 19, 2016 10:37 PM
> To: Huang, Ray; Deucher, Alexander
> Cc: amd-gfx at lists.freedesktop.org; Wang, Ken; Huan, Alvin
> Subject: Re: [PATCH 0/3] drm/amdgpu: implement raster configuration
> 
> On 18/09/16 11:36 AM, Huang Rui wrote:
> > Hi all,
> >
> > This patch set is to introduce the raster configuration for all gfx
> > generations.
> 
> What's the motivation for doing this in the kernel? Mesa will write its
> own values to these registers anyway.

It's to fix the read register ioctl interface.  The raster config registers can be read back by the UMDs, but if the KMD hasn't programmed them, they may have bogus values.  It's mainly for the pro drivers which read the raster config registers to get the baseline before programming them.  Mesa hardcodes the default raster config settings before harvesting.  We arguably should have done it in the kernel as well for mesa (my bad).  At least this way both sides are doing the right thing.

Alex