Hi Am 11.12.19 um 13:36 schrieb Daniel Vetter: > > The udl use-case should be covered already, simply set the flag correctly > at create/import time? It's per-object ... The original udl gem code did this. It was additional state for something that was detectable from the value of import_attach. So udl now overrides vmap and mmap. > btw on why udl does this: Imported bo are usually rendered by real hw, and > reading it uncached/wc is the more defensive setting. It would be kinda > nice if dma-buf would expose this, but I fear dma-api maintainers would > murder us if we even just propose that ... so it's a mess right now. Yeah, in some way it's a variation of the discussion around fbdev memory access that we had before. Best regards Thomas > > btw the issue extends to dma access by devices too, e.g. both i915 and > amdgpu can select the coherency mode at runtime (using e.g. the pcie > no-snoop transaction mode), and we have similar uncoordinated hacks in > there too, like in udl. > -Daniel > >> >> Acked-by: Thomas Zimmermann <tzimmermann@xxxxxxx> >> >> if you prefer to merge v1. >> >>> >>> Best regards >>> Thomas >>> >>>> >>> >> >> -- >> Thomas Zimmermann >> Graphics Driver Developer >> SUSE Software Solutions Germany GmbH >> Maxfeldstr. 5, 90409 Nürnberg, Germany >> (HRB 36809, AG Nürnberg) >> Geschäftsführer: Felix Imendörffer >> > > > > >> _______________________________________________ >> dri-devel mailing list >> dri-devel@xxxxxxxxxxxxxxxxxxxxx >> 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: Felix Imendörffer
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