Messages in this thread | | | Date | Thu, 23 Jun 2022 10:42:49 +0200 | Subject | Re: DMA-buf and uncached system memory | From | Thomas Zimmermann <> |
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Hi
Am 23.06.22 um 10:26 schrieb Christian König: > Am 23.06.22 um 10:13 schrieb Thomas Zimmermann: >> Hi Christian >> >> Am 15.02.21 um 09:58 schrieb Christian König: >>> Hi guys, >>> >>> we are currently working an Freesync and direct scan out from system >>> memory on AMD APUs in A+A laptops. >>> >>> On problem we stumbled over is that our display hardware needs to >>> scan out from uncached system memory and we currently don't have a >>> way to communicate that through DMA-buf. >>> >>> For our specific use case at hand we are going to implement something >>> driver specific, but the question is should we have something more >>> generic for this? >> >> I had a patchset here that extends iosys-map (former dma-buf-map) with >> caching information. I'll post a copy. > > Oh, nice. But why on iosys-map? We need that per DMA-buf.
It's returned via the dma-buf's vmap call within the iosys-map structure. If the dma-buf moves, the following vmap calls always return updated caching information. Maybe it's not quite what you need for Freesync?
I'll use this for format-conversion helpers, which do some optimizations for uncached memory.
Anyway, I have to look for that patch...
Best regards Thomas
> > Thanks, > Christian. > >> >> Sorry for being late to reply. >> >> Best regards >> Thomas >> >>> >>> After all the system memory access pattern is a PCIe extension and as >>> such something generic. >>> >>> Regards, >>> Christian. >>> _______________________________________________ >>> dri-devel mailing list >>> dri-devel@lists.freedesktop.org >>> https://lists.freedesktop.org/mailman/listinfo/dri-devel >> >
-- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Ivo Totev [unhandled content-type:application/pgp-signature] | |