Hi Russell,
On Wed, Aug 7, 2019 at 6:13 PM Russell King - ARM Linux admin
<linux@xxxxxxxxxxxxxxx> wrote:
> Well, the question is what behaviour do we want. The driver's original
> behaviour prior to it breaking was to ignore DMA if it wasn't found
> (e.g. when the DMA driver is a module.)
>
> Your patch restores that behaviour, which is the safest approach.
Thanks for the feedback.
> Audrey's patch has the effect that none of the I2C buses will be
> registered if the DMA driver is a module, until the DMA driver is
> loaded. Since an I2C bus _may_ have the systems RTC on it, not
> probing the I2C bus will cause the RTC not to be read by the kernel
> at boot, leading to the system booting with a unixtime of 0.
That's a very good point.
> I haven't checked what the situation is wrt RTCs on the ZII boards,
> whether they do indeed have external I2C RTCs on them.
Yes, they do have external I2C RTCs. Please check this commit for example:
09fc0dacc ("ARM: dts: imx6qdl-zii-rdu2: Disable the internal RTC")
If Wolfram agrees, I think we can go with my patch then.
Thanks
