[Intel-gfx] [PATCH 10/13] drm/i915: Enable PPGTT command parser checks

[Chris Wilson]

On Wed, Jan 29, 2014 at 01:55:11PM -0800, bradley.d.volkin at intel.com wrote:
> From: Brad Volkin <bradley.d.volkin at intel.com>
> 
> Various commands that access memory have a bit to determine whether
> the graphics address specified in the command should use the GGTT or
> PPGTT for translation. These checks ensure that the bit indicates
> PPGTT translation.
> 
> Most of these checks use the existing bit-checking infrastructure.
> The PIPE_CONTROL and MI_FLUSH_DW commands, however, are multi-function
> commands. The GGTT/PPGTT bit is only relevant for certain uses of the
> command. As such, this change also extends the bit-checking code to
> include a "condition" mask and offset. If the condition mask is non-zero
> then the parser only performs the bit check when the bits specified by
> the condition mask/offset are also non-zero.
> 
> NOTE: At this point in the series PPGTT must be enabled for the parser
> to work correctly. If it's not enabled, userspace will not be setting
> the PPGTT bits the way the parser requires. VLV is the only platform
> where this is a problem, so at this point, we disable parsing for VLV.

That doesn't make sense. Are we not verifying that userspace has set the
bits as appropriate for the hardware setup? So the value we expect
depends upon how we have enabled ppgtt (or not).
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre