[PATCH v5] drivers/tty: amba: defer probing DMA availability until hw_init

[Russell King - ARM Linux]

On Tue, Mar 03, 2015 at 11:06:32AM -0500, Jorge Ramirez-Ortiz wrote:
> On 02/26/2015 11:56 AM, Jorge Ramirez-Ortiz wrote:
> > -	chan = dma_request_slave_channel(dev, "tx");
> > +	uap->dma_probed = true;
> > +
> > +	chan = dma_request_slave_channel_reason(uap_dev, "tx");
> > +	if (IS_ERR(chan)) {
> > +		if (PTR_ERR(chan) == -EPROBE_DEFER) {
> > +			dev_info(uap_dev, "DMA driver not ready\n");

I still object to this.

It _can't_ be right that we plaster the kernel console with these
messages when the is a DMA possible, but the DMA driver is a module
which hasn't been loaded yet.

You probably don't realise it, but init daemons tend to open the
console, write their message, and then close it again.  What your
message above means is that each time an init daemon does that, we
get a "DMA driver not ready" message.

IMHO, that is unacceptable.

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