[Intel-gfx] [PATCH] drm/i915: Enforce that CS packets are qword aligned

[Tvrtko Ursulin]

On 21/07/2017 17:11, Chris Wilson wrote:
> We require the caller to ensure that the packets they wish to emit into
> the CS ring are qword aligned (i.e. have an even number of dwords).
> Double check this.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> ---
>   drivers/gpu/drm/i915/intel_ringbuffer.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index aa59290cb8bf..0b06f66507a0 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -1397,6 +1397,9 @@ u32 *intel_ring_begin(struct drm_i915_gem_request *req,
>   	unsigned int total_bytes;
>   	u32 *cs;
>   
> +	/* Packets must be qword aligned. */
> +	GEM_BUG_ON(num_dwords & 1);
> +
>   	total_bytes = bytes + req->reserved_space;
>   	GEM_BUG_ON(total_bytes > ring->effective_size);
>   
> 

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Regards,

Tvrtko