[PATCH] drm/ttm: soften TTM warnings

[Gerd Hoffmann]

On Wed, Mar 03, 2021 at 04:57:57PM +0100, Christian König wrote:
> QXL indeed unrefs pinned BOs and the warnings are spamming peoples log files.
> 
> Make sure we warn only once until the QXL driver is fixed.

> -	dma_resv_assert_held(bo->base.resv);
> +	if (!bo->deleted)
> +		dma_resv_assert_held(bo->base.resv);

Hmm?  I'm not aware of qxl having problems with this one.
Did I miss something?

> -		if (WARN_ON(bo->pin_count)) {
> +		if (WARN_ON_ONCE(bo->pin_count)) {

Well, as temporary thing this is rather pointless, qxl fix for this one
is already queued in drm-misc-fixes so this would only land after the
qxl fixes ...

But I think using WARN_ON_ONCE() is a good idea in general, especially
in a code path like this where a single bug can easily cause a flood of
stack traces.

Acked-by: Gerd Hoffmann <kraxel at redhat.com>

take care,
  Gerd