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[PATCH] video/aty/mach64_ct.c: fix bogus delay loop

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CT based mach64 cards were reported to hang on sparc64 boxes when
compiled with gcc-4.1.x and later.

Looking at this piece of code, it's no surprise.  A critical
delay was implemented as an empty for() loop, and gcc 4.0.x
and previous did not optimize it away, so we did get a delay.

But gcc-4.1.x and later can optimize it away, and we get crashes.

Use a real udelay() to fix this.  Fix verified on SunBlade100.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Miller 2007-03-05 01:35:36 -08:00 committed by Linus Torvalds
parent 8f48561223
commit 8690ba446d
1 changed files with 1 additions and 2 deletions
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3
drivers/video/aty/mach64_ct.c
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@ -598,7 +598,6 @@ static void aty_resume_pll_ct(const struct fb_info *info,
struct atyfb_par *par = info->par;
if (par->mclk_per != par->xclk_per) {
int i;
/*
* This disables the sclk, crashes the computer as reported:
* aty_st_pll_ct(SPLL_CNTL2, 3, info);
@ -614,7 +613,7 @@ static void aty_resume_pll_ct(const struct fb_info *info,
* helps for Rage Mobilities that sometimes crash when
* we switch to sclk. (Daniel Mantione, 13-05-2003)
*/
for (i=0;i<=0x1ffff;i++);
udelay(500);
}
aty_st_pll_ct(PLL_REF_DIV, pll->ct.pll_ref_div, par);