[Intel-gfx] [PATCH 05/59] drm/i915: Reserve ring buffer space for i915_add_request() commands

[John Harrison]

On 19/03/2015 12:30, John.C.Harrison at Intel.com wrote:
> +void intel_ring_reserved_space_end(struct intel_ringbuffer *ringbuf)
> +{
> +    WARN_ON(!ringbuf->reserved_in_use);
> +    WARN_ON(ringbuf->tail > ringbuf->reserved_tail + 
> ringbuf->reserved_size);
> +
> +    ringbuf->reserved_size   = 0;
> +    ringbuf->reserved_in_use = false;
> +}
> +

So apparently, my reserved size choice was too small for ironlake and 
the above assert is firing. Is there any kind of WARN_ON with printf 
facility in the kernel? It would be useful to have the offending sizes 
included in the message log without having to patch and re-run the 
tests. Or is the official solution to just use DRM_ERROR(...) instead of 
WARN_ON? I guess the stack trace isn't necessary as we know where the 
error is coming from already. But do DRM_ERROR() prints always appear or 
are they conditional on the user enabling them? And would anyone notice 
one anyway? At least with WARN_ONs, people do tend to complain.

Thanks,
John.