RE: [PATCH 1/1] spi: pxa2xx: add driver enabling message

From: Flavio Suligoi
Date: Wed Apr 10 2019 - 08:01:22 EST


> On Wed, Apr 10, 2019 at 11:47:43AM +0000, Flavio Suligoi wrote:
>
> > You have right about to avoid too many boot messages,
> > but in this case, using an x86 machine and with
> > the spi-pxa2xx in DMA mode, so without the message:
>
> > "no DMA channels available, using PIO",
>
> > there is absolutely no indication about the existence
> > of the SPI master controller.
>
> It's totally fine to not have a boot print for the device, the best way
> to find devices if you need them is to look in sysfs anyway.

Ok

> > The second reason is about the DMA/PIO mode indication.
> > With the board I'm using, sometimes the spi-pxa2xx driver can't allocate
> > a DMA channel and works in PIO mode.
>
> > So, with the advice of Jarkko, I think that a valid solution could be:
>
> > 1) remove the "no DMA channels available, using PIO" message
> > 2) add a new message with the indications of:
> > - controller mode (slave or master)
> > - transfer mode (DMA or PIO)
>
> > What do you think about this?
>
> If the system is randomly failing to assign a DMA channel when it should
> then shouldn't we just fix that? A print which is presumably intended
> to prompt the user to reboot to try to get things working doesn't seem
> like a good solution.

Right, I'm just fix the DMA problem (I'm preparing a patch about this)

Flavio