On Mon, Nov 04, 2019 at 06:09:39PM +0100, Stefan Wahren wrote: > Hi Nicolas, > > Am 04.11.19 um 14:54 schrieb Nicolas Saenz Julienne: > > arm64 places the CMA in ZONE_DMA32, which is not good enough for the > > Raspberry Pi 4 since it contains peripherals that can only address the > > first GB of memory. Explicitly place the CMA into that area. > > > > Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx> > > do you want this in Linux 5.5 via devicetree/fixes? In this case please > add an fixes tag. That's not really a fix since AFAICT CMA never worked properly on RPi4 with mainline. For 5.5, I queued the arm64 for-next/zone-dma patches which would allow RPi4 to get a CMA in the correct physical address range. However, since these patches cause a regression on other platforms that don't need a small ZOEN_DMA, my suggestion was to leave the CMA handling for RPi4 as per the current mainline (i.e. broken) and allow CMA from the full ZONE_DMA32 range (second patch in this series). IIUC, this dts patch can be merged independently of the ZONE_DMA patches for arm64 and it may be beneficial for current mainline (even without the arm64/for-next/zone-dma patches). [1] git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux for-next/zone-dma > Otherwise this will be queued for Linux 5.6. I'm happy to queue them together with your ack for 5.5, otherwise I'll only pick the second patch in this series. Thanks. -- Catalin
