[Intel-gfx] [PATCH 1/2] drm/i915: Re-enable the command parser when using PPGTT

[Daniel Vetter]

On Thu, Sep 18, 2014 at 04:26:26PM -0700, bradley.d.volkin at intel.com wrote:
> From: Brad Volkin <bradley.d.volkin at intel.com>
> 
> In commit
> 
> commit 896ab1a5d54269b463a24194c2e4a369103b46d8
> Author: Daniel Vetter <daniel.vetter at ffwll.ch>
> Date:   Wed Aug 6 15:04:51 2014 +0200
> 
>     drm/i915: Fix up checks for aliasing ppgtt
> 
> it looks like we accidentally inverted the check that the command
> parser should only run when the driver enables some form of PPGTT.
> 
> Testcase: igt/gem_exec_parse
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Signed-off-by: Brad Volkin <bradley.d.volkin at intel.com>

Ouch, thanks for spotting&fixing this.
> ---
> 
> At this point all platforms that use the command parser should have at
> least aliasing PPGTT enabled I believe, so if you confirm then feel free
> to delete the comment about VLV and make this check stricter - maybe
> WARN_ON - when applying the patch.

Yeah, vlv now has ppgtt enabled (full ppgtt now even), except for some
early pre-prod stuff where it's broken. So dropped the comment.

Unfortunately our QA still has a bunch of these vlv around, so we can't
add a WARN_ON without totally upsetting them :( But I guess we should do
that once we enable the cmd parser for real and tell them to get new
machines.
-Daniel
> 
>  drivers/gpu/drm/i915/i915_cmd_parser.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c b/drivers/gpu/drm/i915/i915_cmd_parser.c
> index c45856b..fb24dae 100644
> --- a/drivers/gpu/drm/i915/i915_cmd_parser.c
> +++ b/drivers/gpu/drm/i915/i915_cmd_parser.c
> @@ -850,7 +850,7 @@ bool i915_needs_cmd_parser(struct intel_engine_cs *ring)
>  	 * disabled. That will cause all of the parser's PPGTT checks to
>  	 * fail. For now, disable parsing when PPGTT is off.
>  	 */
> -	if (USES_PPGTT(ring->dev))
> +	if (!USES_PPGTT(ring->dev))
>  		return false;
>  
>  	return (i915.enable_cmd_parser == 1);
> -- 
> 1.8.3.2
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch