On Tue, May 02, 2017 at 08:07:44PM +0530, Sekhar Nori wrote:
> On Tuesday 02 May 2017 06:24 PM, Bin Liu wrote:
> > On Tue, May 02, 2017 at 11:21:54AM +0530, Sekhar Nori wrote:
> >> Hi Alexandre,
> >>
> >> On Friday 28 April 2017 09:34 PM, Alexandre Bailon wrote:
> >>> If dma_request_slave_channel() failed to return a channel,
> >>> then the driver will print an error and request to defer probe.
> >>> Update the error message to explain we are defrering probe.
> >>>
> >>> Signed-off-by: Alexandre Bailon <abailon@xxxxxxxxxxxx>
> >>> ---
> >>> drivers/usb/musb/musb_cppi41.c | 1 +
> >>> 1 file changed, 1 insertion(+)
> >>>
> >>> diff --git a/drivers/usb/musb/musb_cppi41.c b/drivers/usb/musb/musb_cppi41.c
> >>> index e7c8b1b..e6b9161 100644
> >>> --- a/drivers/usb/musb/musb_cppi41.c
> >>> +++ b/drivers/usb/musb/musb_cppi41.c
> >>> @@ -676,6 +676,7 @@ static int cppi41_dma_controller_start(struct cppi41_dma_controller *controller)
> >>> dc = dma_request_slave_channel(dev->parent, str);
> >>> if (!dc) {
> >>> dev_err(dev, "Failed to request %s.\n", str);
> >>> + dev_info(dev, "Deferring probe.\n");
> >>> ret = -EPROBE_DEFER;
> >>> goto err;
> >>> }
> >>
> >> It looks like you will be better-off using dma_request_chan() instead so
> >> you can get an error pointer back and not return -EPROBE_DEFER
> >> irrespective of the actual error.
> >
> > I thought about it, but -EPROBE_DEFER is the only error code returned in
> > dma_request_chan(), so nothing else to distinguish here, improving the
> > dev_err message would be an simpler fix.
>
> The kernel-doc comment for dma_request_chan() says it can return any
> error pointer and not just -EPROBE_DEFER. So rather than depending on
> the current implementation which might change couple of kernel versions
> later, we should assume any error pointer can be returned.
Fair enough :)
Regards,
-Bin.
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