[Cbe-oss-dev] [PATCH 1/5 v2] usb: Fix PS3 EHCI suspend

[Antonio Ospite]

On Fri, 2 Dec 2011 14:26:12 +0100
Geert Uytterhoeven <geert at linux-m68k.org> wrote:

> Hi Antonio,
> 
> On Fri, Dec 2, 2011 at 10:30, Antonio Ospite <ospite at studenti.unina.it> wrote:
> > On Thu, 1 Dec 2011 16:19:18 -0800
> > Geoff Levand <geoff at infradead.org> wrote:
> >
> > [...]
> >> @@ -236,6 +240,30 @@ static int handshake_on_error_set_halt(struct ehci_hcd *ehci, void __iomem *ptr,
> >>       int error;
> >>
> >>       error = handshake(ehci, ptr, mask, done, usec);
> >> +
> >> +     /*
> >> +      * The EHCI controller of the Cell Super Companion Chip used in the
> >> +      * PS3 will stop the root hub after all root hub ports are suspended.
> >> +      * When in this condition handshake will return -ETIMEDOUT.  The
> >> +      * STS_HLT bit will not be set, so inspection of the frame index is
> >> +      * used here to test for the condition.  If the condition is found
> >> +      * return success to allow the USB suspend to complete.
> >> +      */
> >> +
> >> +#if defined(CONFIG_USB_SUSPEND) && defined(CONFIG_PPC_PS3)
> >> +     if (firmware_has_feature(FW_FEATURE_PS3_LV1) && error == -ETIMEDOUT) {
> >> +#else
> >> +     if (0) {
> >> +#endif
> >
> > Sometime I still have these doubts, forgive me:
> > Geoff is this done this way to keep the #endif as near as possible to
> > the #if? I mean wouldn't it be equivalent (even if one would be left out
> > by the preprocessor and the other by the compiler) to put the whole
> > conditional block inside the #if defined(CONFIG_PPC_PS3)?
> 
> The advantage of the way Geoff did it is that the compiler will detect if
> someone breaks compilation for PS3 inside the block. With a big #ifdef
> around the block, only PS3 users (and linux-next) will notice.
> 

I see, thanks Geert.

Regards,
   Antonio

-- 
Antonio Ospite
http://ao2.it

PGP public key ID: 0x4553B001

A: Because it messes up the order in which people normally read text.
   See http://en.wikipedia.org/wiki/Posting_style
Q: Why is top-posting such a bad thing?
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