[Bug 2091380] Re: root permissions required to r/w to DMA heap for libpisp on RPi5

[Dave Jones]

This should be fixed in ubuntu-raspi-settings by granting access to
/dev/dma_heap/linux,cma via the uaccess mechanism. After discussion with
the kernel team, this should be reasonably safe.

** Also affects: ubuntu-raspi-settings (Ubuntu)
   Importance: Undecided
       Status: New

** Changed in: ubuntu-raspi-settings (Ubuntu)
     Assignee: (unassigned) => Dave Jones (waveform)

** Changed in: ubuntu-raspi-settings (Ubuntu)
    Milestone: None => ubuntu-25.04

** Changed in: libcamera (Ubuntu)
    Milestone: ubuntu-25.04-feature-freeze => None

** Changed in: ubuntu-raspi-settings (Ubuntu)
       Status: New => Confirmed

** Changed in: libcamera (Ubuntu)
       Status: Confirmed => Invalid

** Changed in: ubuntu-raspi-settings (Ubuntu)
   Importance: Undecided => High

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https://bugs.launchpad.net/bugs/2091380

Title:
  root permissions required to r/w to DMA heap for libpisp on RPi5

Status in libcamera package in Ubuntu:
  Invalid
Status in ubuntu-raspi-settings package in Ubuntu:
  Confirmed

Bug description:
  This affects libcamera on the Raspberry Pi 5. The new libpisp and PiSP driver (https://bugs.launchpad.net/ubuntu/+bug/2089646 and https://code.launchpad.net/~r41k0u/ubuntu/+source/libcamera/+git/libcamera/+merge/477052) needs to r/w to /dev/dma_heap/linux,cma
  /dev/dma_heap/limux,cma only has r/w permissions for the root user. This needs to be worked around to make cameras work on RPi5.

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