On 02/07/2020 15:18, Daniel Vetter wrote:
On Thu, Jul 02, 2020 at 09:23:11AM +0000, Simon Ser wrote:
On Thursday, July 2, 2020 9:47 AM, Neil Armstrong narmstrong@baylibre.com wrote:
Finally is also adds the Scatter Memory layout, meaning the header contains IOMMU references to the compressed frames content to optimize memory access and layout.
In this mode, only the header memory address is needed, thus the content memory organization is tied to the current producer execution and cannot be saved/dumped neither transferrable between Amlogic SoCs supporting this modifier.
Still not sure how to handle this one, since this breaks fundamental assumptions about modifiers.
I wonder whether we should require special allocations for these, and then just outright reject mmap on these buffers. mmap on dma-buf isn't a required feature.
Yes, it's the plan to reject mmap on these buffers, but it can't be explained in the modifiers description and it's a requirement of the producer, not the consumer.
That would make sure that userspace cannot look at them.
Also I'm kinda suspecting that there's not unlimited amounts of this magic invisible storage available anyway. -Daniel