Am 18.08.20 um 10:27 schrieb Gerd Hoffmann:

On Tue, Aug 18, 2020 at 09:57:59AM +0200, Christian König wrote:

quoted

Am 18.08.20 um 09:48 schrieb Gerd Hoffmann:

quoted

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@redhat.com>

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).

Yeah, that's the problem patch 2/2 never showed up here :)

quoted

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?

That is probably the best approach, yes.

For Intel and AMD it could even be global/constant, but it certainly 
doesn't needs to be kept around for each buffer.

Christian.

take care,
   Gerd

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel