vino_mtune_dmrbpages

Description

The vino_mtune_dmrbpages parameter limits the size of the DMA descriptor table used by the VINO video capture. This in turn limits how many pages allocated to the Digital Media Ring Buffers are usable when capturing video. The number of pages in vino_mtune_dmrbpages is what the DMRB size specifically for VINO is limited to when allocated.

Value

Default: 0 (auto-configure)

If this parameter is set to zero, then a default based on the amount of memory available at run time is used. If a limit of less than that is desired, set this variable to the maximum number of pages that the ring buffers can use. A value of -1 indicates do not preallocate any space for VINO DMA descriptors.

Notes

Note that if a DMA descriptor table size is needed that is greater than the size specified here and cannot be allocated contiguously at run time (possibly due to memory fragmentation), then the video transfer will not be started, and will return an ENOMEM error. The error recovery is to attempt the capture with a smaller DMRB.