Re: [Qemu-devel] [PULL 1/6] audio/hda: create millisecond timers that handle IO

[Peter Maydell <peter.maydell@linaro.org>]

On 25 June 2018 at 14:12, Gerd Hoffmann <kraxel@redhat.com> wrote:
> Currently, the HDA device tries to sync itself with the QEMU audio
> backend by waiting for the guest driver to handle buffer completion
> interrupts. This causes the backend to often read too much data from the
> device, as well as running out of data whenever the guest takes too long
> to handle the interrupt.
>
> According to the HDA specification, the guest is also not required to
> use interrupts, but can also sync itself by polling the LPIB registers.
>
> This patch will introduce high frequency (1000Hz) timers that interface
> with the device and allow for much smoother emulation of the LPIB
> registers. Since the timing is now provided by these timers, the need
> to wait for buffer completion interrupts also ceases.

> +static inline int64_t hda_bytes_per_second(HDAAudioStream *st)
> +{
> +    return 2 * st->as.nchannels * st->as.freq;
> +}

Hi; Coverity warns about this expression because the
multiplication is done as a 32-bit multiply and the
result is returned as a 64-bit (CID 1393631). As usual,
a suitable cast would fix it.

thanks
-- PMM