Re: [PATCH 1/2] drm: allow limiting the scatter list size.

[Gerd Hoffmann]

On Tue, Aug 18, 2020 at 09:57:59AM +0200, Christian König wrote:
> Am 18.08.20 um 09:48 schrieb Gerd Hoffmann:
> > Add max_segment argument to drm_prime_pages_to_sg().  When set pass it
> > through to the __sg_alloc_table_from_pages() call, otherwise use
> > SCATTERLIST_MAX_SEGMENT.
> > 
> > Also add max_segment field to gem objects and pass it to
> > drm_prime_pages_to_sg() calls in drivers and helpers.
> > 
> > Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
> 
> I'm missing an explanation why this should be useful (it certainly is).

virtio-gpu needs this to work properly with SEV (see patch 2/2 of this
series).

> And the maximum segment size seems misplaced in the GEM object. This is
> usually a property of the device or even completely constant.

Placing it in drm_device instead would indeed work for virtio-gpu, so I
guess you are suggesting that instead?

take care,
  Gerd