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Date: Mon, 25 Jul 2011 22:42:50 +0100
From: Alan Cox <alan@linux.intel.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Ryan Mallon <rmallon@gmail.com>, Jesper Juhl <jj@chaosbits.net>,
        linux-kernel@vger.kernel.org, Greg Kroah-Hartman <gregkh@suse.de>,
        devel@driverdev.osuosl.org
Subject: Re: GMA500: ERROR: "__bad_udelay" undefined!
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On Mon, 25 Jul 2011 23:08:42 +0200
Arnd Bergmann <arnd@arndb.de> wrote:

> On Monday 25 July 2011 11:28:44 Ryan Mallon wrote:
> > 
> > diff --git a/drivers/staging/gma500/psb_intel_display.c
> > b/drivers/staging/gma500/psb_intel_display.c index 4f47d09..09e378d
> > 100644 --- a/drivers/staging/gma500/psb_intel_display.c
> > +++ b/drivers/staging/gma500/psb_intel_display.c
> > @@ -331,7 +331,7 @@ static bool psb_intel_find_best_PLL(struct
> > drm_crtc *crtc, int target, void psb_intel_wait_for_vblank(struct
> > drm_device *dev) {
> >         /* Wait for 20ms, i.e. one cycle at 50hz. */
> > -       udelay(20000);
> > +       mdelay(20);
> >   }
> > 
> >   int psb_intel_pipe_set_base(struct drm_crtc *crtc,
> 
> A 20 ms busy wait is rather nasty. Can't this be replaced with a
> sleeping wait (msleep)?

Don't know yet - its on the fixme list to dig into - I think the answer
is some cases but not all.