Re: [PATCH] PCI: imx6:don't sleep in atomic context

[Lucas Stach <l.stach@pengutronix.de>]

Am Dienstag, den 10.11.2015, 10:28 +0100 schrieb Arnd Bergmann:
> On Tuesday 10 November 2015 09:41:18 Lucas Stach wrote:
> > > diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
> > > index 233a196..9769b13 100644
> > > --- a/drivers/pci/host/pci-imx6.c
> > > +++ b/drivers/pci/host/pci-imx6.c
> > > @@ -499,7 +499,7 @@ static int imx6_pcie_link_up(struct pcie_port *pp)
> > >                * Wait a little bit, then re-check if the link finished
> > >                * the training.
> > >                */
> > > -             usleep_range(1000, 2000);
> > > +             mdelay(1000);
> > 
> > A mdelay(1000) is a whole different timescale than a usleep(1000). If
> > this patch works for you with mdelay(1) or maybe mdelay(2) I would be
> > fine with it.
> 
> mdelay(1) is still a really long time to block the CPU for, on potentially
> every config space access.
> 
> Everybody else just returns the link status here, which seems to be
> the better alternative. If you need to delay the startup, better have
> a msleep(1) loop in the initial probe function where you are allowed to
> sleep.
> 
Yes, it's somewhere on my TODO list to rework the link-up handling here,
but as there are quite a few timing and ordering implications in that
code, this needs a good thought and a good deal of testing. So I'm
inclined to ACK the current patch to get rid of the obvious bug and sort
things out properly in a follow on patchset.

Regards,
Lucas

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