On 3/25/25 19:36, Christian König wrote:
> Am 25.03.25 um 00:07 schrieb Bert Karwatzki:
>> Here's the dmesg from linux-next-6.14-rc7-next20250321 (CONFIG_PCI_P2PDMA
>> not set)
>> The memory ranges of (afe00000000-affffffffff) or
>> (3ffe00000000-3fffffffffff) are
>> mentioned in neither of them.
>
> Ugh, next time either in two mails or as attachment please. I had to separate
> the logs manually again.
>
> The BIOS programs multiple root PCIe resources:
> [ 0.310962] [ T1] pci_bus 0000:00: root bus resource [mem
> 0x000a0000-0x000dffff window]
> [ 0.310963] [ T1] pci_bus 0000:00: root bus resource [mem
> 0xf0000000-0xfcffffff window]
> [ 0.310965] [ T1] pci_bus 0000:00: root bus resource [mem
> 0x1010000000-0xffffffffff window]
>
> But by default all BARs end up in the 0xf0000000-0xfcffffff window and are so
> accessible to the iGPU.
>
> So I don't see a reason why dma_addressing_limited() should return true.
>
Because of
if (min_not_zero(dma_get_mask(dev), dev->bus_dma_limit) <
dma_get_required_mask(dev))
IIRC, dma_get_required_mask is set to 46 bits (based on previous logs) for the
iGPU
"[ 3.965669] [ T328] dma_addressing_limited: mask = 0xfffffffffff
bus_dma_limit = 0x0 required_mask = 0x3fffffffffff
[ 3.965671] [ T328] dma_addressing_limited: returning true
[ 3.965672] [ T328] amdgpu 0000:08:00.0: amdgpu: amdgpu_ttm_init: calling
ttm_device_init() with use_dma32 = 1"
I am not sure why that is the case at the moment
Balbir
