[Intel-gfx] [PATCH] drm/i915/bdw: Fix 4g GGTT insert entries regression

[Jani Nikula]

On Wed, 05 Mar 2014, Ben Widawsky <benjamin.widawsky at intel.com> wrote:
> The PDE needs to wrap after writing all the PTEs. Quite a small/silly
> bug to find in the massive change. It was introduced:
> commit 307dc4f99f6d3a74a78b0e776838f35b2004f14d
> Author: Ben Widawsky <benjamin.widawsky at intel.com>
> Date:   Thu Feb 20 11:51:21 2014 -0800
>
>     drm/i915/bdw: Reorganize PT allocations

As noted in the bug, the commit merged to dinq is correct, and the
commit referenced above apparently only lives in some temporary branch.

BR,
Jani.


>
> I can't actually test this patch at the moment because my Broadwell is
> unresponsive. This should be squashed if possible.
>
> Cc: Imre Deak <imre.deak at intel.com>
> Reported-by: Timo Aaltonen <tjaalton at ubuntu.com>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=75763
> Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
> ---
>  drivers/gpu/drm/i915/i915_gem_gtt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index 5462037..2bde703 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -335,7 +335,7 @@ static void gen8_ppgtt_insert_entries(struct i915_address_space *vm,
>  		if (++pte == GEN8_PTES_PER_PAGE) {
>  			kunmap_atomic(pt_vaddr);
>  			pt_vaddr = NULL;
> -			if (pde + 1 == GEN8_PDES_PER_PAGE) {
> +			if (++pde == GEN8_PDES_PER_PAGE) {
>  				pdpe++;
>  				pde = 0;
>  			}
> -- 
> 1.9.0
>
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-- 
Jani Nikula, Intel Open Source Technology Center