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| author | Andrei Gherzan <andrei@gherzan.ro> | 2019-07-24 16:10:40 +0100 |
|---|---|---|
| committer | Andrei Gherzan <andrei@gherzan.ro> | 2019-07-24 16:10:42 +0100 |
| commit | 009049e728d6a7529c853accb3de169fd17b6d5c (patch) | |
| tree | e59e3843b361a7533d6649c98e871ed58cbd6617 /docs | |
| parent | 0d641c8fa918b1c5ecce2cb9918c47bb3c4e1510 (diff) | |
| download | meta-raspberrypi-ag/rpi4-mem.tar.gz | |
raspberrypi4-64.conf: Limit RAM to 3Gag/rpi4-mem
The PCI controller on the Raspberry Pi 4 acts as a DMA controller and can
only address the first 3Gb[1] of the memory space. On 32bit this was
addressed by implementing bouncing buffers[2] but this currently has no
support for arm64. In order to have working USB, as a workaround, we
limit the ram to 3G.
Fixes #446
[1] https://github.com/raspberrypi/linux/issues/3093
[2] https://github.com/raspberrypi/linux/blob/rpi-4.19.y/drivers/pci/controller/pcie-brcmstb-bounce.c
Signed-off-by: Andrei Gherzan <andrei@gherzan.ro>
Diffstat (limited to 'docs')
0 files changed, 0 insertions, 0 deletions