[Intel-gfx] [PATCH] drm/i915/guc: Fix doorbell id selection

[Daniele Ceraolo Spurio]

On 30/05/17 17:05, Michel Thierry wrote:
> We are passing parameters in the wrong order to find next zero bit, and
> when it doesn't find anything it returns size (offset in the code), which
> is always zero.
>
> For reference the function is defined as:
> find_next_bit( *addr, size, offset )
>
> The incorrect parameter order was added by commit abddffdf3620e
> ("drm/i915/guc: Sanitize GuC client initialization"). Luckily, currently
> we only use a single guc client and a single doorbell, which happens to be
> zero; therefore it isn't necessary to backport this fix (which would be for
> v4.12).
>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> Cc: Oscar Mateo <oscar.mateo at intel.com>
> Signed-off-by: Michel Thierry <michel.thierry at intel.com>
> ---

Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>

Thanks,
Daniele

>  drivers/gpu/drm/i915/i915_guc_submission.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
> index fb936bb5cb93..ec391ef981aa 100644
> --- a/drivers/gpu/drm/i915/i915_guc_submission.c
> +++ b/drivers/gpu/drm/i915/i915_guc_submission.c
> @@ -105,7 +105,7 @@ static int __reserve_doorbell(struct i915_guc_client *client)
>  		end += offset;
>  	}
>
> -	id = find_next_zero_bit(client->guc->doorbell_bitmap, offset, end);
> +	id = find_next_zero_bit(client->guc->doorbell_bitmap, end, offset);
>  	if (id == end)
>  		return -ENOSPC;
>
>