Re: [Qemu-discuss] Intel HDA and DMA

[Peter Maydell]

On 4 May 2018 at 15:08, Mathieu Barbe <address@hidden> wrote:
> Hi everyone,
> I'm new here and I'm a computer science student.
>
> I have a issue with my personal OS.

> If I replace the pci_dma_read function with :
>         cpu_physical_memory_read(addr, buf, 16);
>
> It works, buffer containing my data.
> It seems that the sound card cannot access at memory through the DMA.
>
> Can you tell me if we forgot to configure something for PCI DMA?
> Maybe we should configure it?

Is your OS remembering to turn on the PCI bus master enable bit
in the PCI command register? That needs to be set for DMA
by the PCI card to be permitted.

thanks
-- PMM